VRBRAIN: some updates from PX4 Firmware
stm32_i2c: handle more error conditions on I2C bus
mtd driver: add missing SPI header
stm32_serial: fixed spelling of FLOWCONTROL config option in stm32 serial code
CONFIG_ARCH_IRQPRIO: some updates from PX4 NuttX
VRBRAIN: change I2C timeout from 10ms to 1ms
VRBRAIN: new pre-compiled archives for all VR Brain boards
Modified the management of HRT, PPMSUM and PWM IN for VR Micro Brain 5
Modified the management of HRT, PPMSUM and PWM IN for VR Brain 4.5 and VR Brain 5 Standard and Professional
Changed PWMIN to PWMOUT and added digital switch with PPMSUM or SBUS
Added digital switch
VRBRAIN: fix an incorrect mapping and setting of PWM output's timers