This commit adds a barbones FTDI FT80x driver.  It is untested (I don't even have hardware yet and, hence, it is marked as EXPERIMENTAL

Squashed commit of the following:

    drivers/lcd:  Finishes off basic FT80X.  Still missing some niceties.
    drivers/lcd: Rethink FT80X display list interface.
    drivers/lcd:  More FT800x display list logic.  Still not complete.
    drivers/lcd:  Add some basic FT80x initialization logic.
    drivers/lcd:  Add ft80x display list IOCTL framework.  Still missing low level display list operations.
    drivers/lcd:  FT80x driver cannot be a standard LCD driver but must, instead, be a custom character driver.
    drivers/lcd:  Add FT800 co-processor commands and display list helpers.
    drivers/lcd:  Add SPI interface and framework for the initialization and the basic LCD driver.
    drivers/lcd:  Add beginnings of some FT80x implementation.
    drivers/lcd:  Add definitions for the FTDI FT801 part
    include/nuttx/lcd/ft800.h:  Add initial FT800 interface definition.
    drivers/lcd:  Add ft800 header file.

include/lcd:  Eliminate a warning from an SSD1306 header file by adding a forward reference to struct i2c_master_s.

lc823450 smp test

* sched/clock: Replace critical section APIs with spin lock APIs in clock_gettime.c

    This change will improve performance for SMP systems but nothing
    changes for non-SMP systems. (Pls see include/nuttx/irq.h)

Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>

* sched/sched: Remove unnecessary DEBUGASSERT in sched_removereadytorun.c

    In SMP mode, rtrtcb is not always at the g_readytorun.head.
    This change removes DEBUGASSERT() to avoid this condition.

Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>

Approved-by: Gregory Nutt <gnutt@nuttx.org>

LIS3DH: Fix missing shift when writing output data rate to register

Approved-by: Gregory Nutt <gnutt@nuttx.org>

stm32f103-minimum/src/:  Fix newly introduced errors and warnings.  Most cause by removing illegal inclusions from board.h.

Fix signal handing for smp

* sched/signal: Remove SMP related logic in sig_dispatch.c

    This change prevents from a deadlock in up_schedulesigaction.c
    where inter-CPU signal handling is actually implemented.

Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>

* arch/arm/src/armv7-m: Fix signal handling for SMP

    In previous implementation, signal handling for SMP was incorrect.
    Thus, for example, if an inter-CPU signal happened an incorret tcb
    was signaled and caused ASSERT().

    This change fixes the issues and works for both inter-CPU signal
    handling and signal handling on the same CPU.

Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>

Approved-by: Gregory Nutt <gnutt@nuttx.org>

configs/flipnclick-pic32mz and -sam3x:  Generalize naming.  HiletGo is one SSD1306 LCD, but the logic should work with any SSD1306.  Naming need to be generalized to SSD1306 to make this reusability clear.

Added support for LIS3DH accelerometer sensor.

* Added support for LIS3DH accelerometer sensor.

* Fix line length

* Fix more line lengthts

Approved-by: Gregory Nutt <gnutt@nuttx.org>

net/tcp:  Fixed bad return value handling in psock_tcp_send().  send() expects psock_tcp_send() to return a negated errno value, not -1 with the errno set (GN: I added same change for tcp_send_buffered.c which has the same issue as tcp_send_unbuffered.c)

SAMDL DMA fixes and experimental SPI support

* SAMDL: Fix DMA controller support

* SAMDL: Added experimental DMA support to SPI driver. spi_exchange() uses a pair of DMA channels for TX and RX

Approved-by: Gregory Nutt <gnutt@nuttx.org>

disable LPC17 FDR when not used (second fix)

if a boot loader sets the fractional divider (FDR) the baud rate in
nuttx will be wrong (multiplied by this fraction).

This also has to be added to lpc17_lowputc.c

Unfortunately the constant used for shifting the bits was wrong in the header file, so it took some time to realize this...

Approved-by: Gregory Nutt <gnutt@nuttx.org>

Master

stm32_hritm: add interface to set timer frequency, fix slave timers reset configuration, change POWER_INFO to TIMER_INFO

Approved-by: Gregory Nutt <gnutt@nuttx.org>

SAMDL: Added loading factory USB calibration data from NVRAM

Approved-by: Gregory Nutt <gnutt@nuttx.org>

SAMDL: Fix EIC interrupt edge sensitivity for pin numbers > 8

Approved-by: Gregory Nutt <gnutt@nuttx.org>

SAMDL: Added FDPLL clock support. Fixed sequence of OSC32K calibration setup

* SAMDL: Added FDPLL clock support. Fixed sequence of OSC32K calibration setup

* fixed code style

Approved-by: Gregory Nutt <gnutt@nuttx.org>

    configs/flipnclick-pic32mz:  Add an nxlines configuration for use in testing the custom HiletGo Click board.
    arch/mips/src/pic32mz:  Correct some SPI-related typos.  configs/flipnclick-pic32mz: Finishes integration of HiletGo OLED. drivers/lcd:  Finish support for HiletGo OLED.
    drivers/lcd:  Add configuration support for HiletGo OLED.  configs/flipnclick-pic32mz:  Add board support for HiletGo OLED.