configs/freedom-k28f:  Add button and LED support.
    arch/arm/src/kinetis:  Fix a couple of additional compile problems.
    arch/arm/src/kinetis/chip and configs/freedom-k28f:  Add things needed for a successful build.  Still need board LED definitions.

     arch/arm/src/kinetis:  The K28F Kinetis MPU is almost the same as the K66F MPU.
     arch/arm/src/kinetis:  The K28F Kinetis FMC is the same as the K66F FMC.

configs/photon: Adds RGB led support

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

drivers/sensors: Adds support for INA3221 power sensor. This has a 3 channel bus/shunt voltage pairs.

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

drivers/rgbled: Adds support for multichannel PWM (multiple PWM channels on a single timer)

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

fs/nfs/rpc_clnt.c:  Commit 091e3f73 broke the NFS client.  sendto() can (correctly) no lnoger by used with a connected UDP socket.  In that case, send() must be used instead.

This commits adds initial support for the Kinetis Freedom-K28F board.  Not you ready for prime time.

Squashed commit of the following:

    arch/arm/src/kinetis:  A fixes from first (unsuccessful) attempt to build the Freedom-K28F configuration.
    configs/freedom-k28f:  Add basic board support for Freedom-K28F.  Initial commit is basically just the Teensy-3.x brought up to date and with name changes.

arch/arm/src/lpc17xx: This commit adds a configurable option to allow using a part of LPC17xx's internal flash memory as a Memory Technology Device via NuttX' mtd_progmem infrastructure. Tested with LPC1769.

configs/imxrt1050-evk:  This commit adds support for the imxrt button.  I haven't been able to get GPIO 5 to work so I have replaced the button with GPIO1 pin24. It is right next to the button so I just wire it to the existing user button for testing.

  imxrt_gpioirq.c
    - Add check for interrupt mask register before dispatching ISR. The GPIO_ISR bits are set independent of the GPIO_IMR bits.
  imxrt_irq.c
    - fixed a range check for extint in function imxrt_irqinfo().

Squashed commit of the following:

    arch/arm/src/kinetis:  Add K28F memory map.
    arch/arm/src/include/kinetis and src/kinetis:  Add basic chip features and interrupt-related definitions for the K28F

configs/nrf52-pca10040:  Fix an error in the name of an included file.  This was introduced with the previous change to this file.

progmem interface: Discern r/w and erase page sizes.  Introduce new up_progmem_erasesize architecture API to be able to communicate the read/write page size independently from erase page size.  Implement up_progmem_erasesize for all architectures that already support progmem, assuming that for those architectures the sizes of both read/write and erase pages are identical.

arch/arm/src/nrf52:  Fix several inconsistencies in naming.  Mostly cosmetic but one was causing a compiler warning.

include/nuttx/wireless/bluetooth:  Move Bluetooth header files from include/nuttx/wireless to include/nuttx/wireless/bluetooth for symmetry with other wireless technologies.

arch/arm/src/tiva:  Implemented Flash CONFIG_MTD_BYTE_WRITE for TM4c1294.  Implemented the tiva_write function which will write an arbitrary number of bytes to flash (in multiple of 4).

arch/arm/src/tiva:  Implements an EEPROM driver in compliance with MTD driver as provided by NUTTX for TM4C1294.  The EEPROM driver currently supports only two functionalities - read bytes(multiple of 4) and write bytes (multiple of 4).

Squashed commit of the following:

Author: Gregory Nutt <gnutt@nuttx.org>
    Fix some spacing
    arch/arm/src/tiva:  Verify that the EEPROM driver at least builds.
    arch/arm/src/tiva:  Move unused function added to tm4c129_syscontrol.c to tiva_eeprom.c where it is actually used.
    arch/arm/src/tiva:  Reorganize EEPROM register definitions so that the file organization is more like other platforms.
    arch/arm/src/tiva:  Trying to resolve EEPROM register addressing.  Still some issues.
    arch/arm/src/tiva:  Ran uncrustify on tiva_eeprom.c
    arch/arm/src/tiva:  EEPROM driver is a little closer to coding standard.  Still a way to go.

Author: Shirshak Sengupta <sgshirshak@gmail.com>
    arch/arm/src/tiva: Implemented EEPROM driver in compliance with MTD driver as provided by NUTTX for TM4C1294. The EEPROM driver needs to be initialized by calling the function tiva_EEPROMInit The EEPROM driver currently supports only two functionalities - read bytes(multiple of 4) and write bytes (multiple of 4). Note - Rest of the features of EEPROM will be implemented in the future.

Makefile.unix:  There is a sort command in the 'make savedefconfig' file.  I found that sort behaves differently on different platforms based on the environment variable LC_ALL.  Now, Makefile.unix will force LC_ALL=C just for the sort command so that we can all generate equivalent defconfig files.