STM32F4xx: added support for STM32F411
GPIOv2: fixed usage of non existing GPIO ports in bitmask
STM32F4xx: fixed bad wait states for STM32F401
boards: added ST_NUCLEO_F411RE
ARMCM4-STM32F401RE-NUCLEO: fixed EXT lines in mcuconf.h
ARMCM4-STM32F401C-DISCOVERY: fixed EXT lines in mcuconf.h