Changes to px4fmu-v4 for upstream Nuttx and hardfault logging

cmake/configs/nuttx_px4fmu-v4_default.cmake

nuttx-configs/px4fmu-v4/include/board.h

nuttx-configs/px4fmu-v4/nsh/Make.defs

nuttx-configs/px4fmu-v4/nsh/appconfig

nuttx-configs/px4fmu-v4/nsh/defconfig

nuttx-configs/px4fmu-v4/src/Makefile

src/drivers/boards/px4fmu-v4/board_config.h

src/drivers/boards/px4fmu-v4/px4fmu_can.c

src/drivers/boards/px4fmu-v4/px4fmu_init.c

src/drivers/boards/px4fmu-v4/px4fmu_led.c

src/drivers/boards/px4fmu-v4/px4fmu_spi.c

src/drivers/boards/px4fmu-v4/px4fmu_usb.c