User could enable SERIAL_XON_XOFF on USB-native devices and it would not be enabled without warning, but M115 would report the capability as available.
* Enable hardware serial ports on LPC1768
* Fix compilation errors with other HALs
* FIx order of includes in LPC1768 HAL main.cpp
* Add support for RX_BUFFER_SIZE and TX_BUFFER_SIZE options in Configuration_adv.h