FS: Add logic to detach a file structure from a file descriptor.  This is for use only within the OS.  It permits an open file or driver to be used across multiple threads.

lcd/Kconfig, Make.defs: Remove dependency of CONFIG_LCD_NXDRIVER for building non-graphic, SLCD drivers.

get I2C working for STM32L4

1-wire:  Initialization/uninitialization functions are not use MCU-independent up_ naming.  Should use STM32-specific stm32_ naming.  These are not globally accessible but only accessible from STM32 board logic.

get I2C working.  some more work regarding clocking computation is needed, as is some inhertited 'todo's from the basis code.  but it does work with the devices tested so far.

STM32 CAN: Add support for both RX FIFOs

Additional configuration option to enable SST26 driver debug output.  Using comming FS debug output generates too much output.

complete logic in 'create stack' and 'use stack' to support stack coloration.  Fix some booboos breaking compatibility with TLS in libc.

altered pin defs for I2C pins; these needed to be specified as open-drain (otherwise they are push-pull)

complete logic in 'create stack' and 'use stack' to support stack coloration.  Fix some booboos breaking compatibility with TLS in libc.

Update Nucleo F303RE and STM32F4Discovery uavcan configurations

*  This driver supports the 'I2C lcd backpack' design that is based on the PCF8574 io expander.  There's a myriad of different vendors of such, but they are principally the same, save wiring and minor features like jumpers for I2C addresses.  This driver supports known and unknown variants.
*  The interface board supports HD44780-based LCD modules up to 4x32, and this driver accommodates all those formats.

This fix removes the disabling of the whole USB peripheral on suspend
interrupt. Its enough to freeze the clock instead.

When disabling the whole peripheral, the next wakeup-interrupt comes
up with an disabled clocking. The unfreeze clock has no effect, because
the master clock is disabled. This makes all registers, including the
IDR unwriteable and the IRQ falls in an endless loop blocking the whole
system.

Furthermore the disabling of the peripheral clock prevents hotplugging
or reconnecting the USB.