Unconfigure GPIO pins when closing a serial port to prevent back effects from back-powering on the TX pin. From Kosma Moczek

Add support for a network device IOCTL to access PHY registers.  Ioctls only implemented for STM32.  From Lazlo

Move the remaining files from include/nuttx/net/uip to include/nuttx/net; Rename *_internal.h header files in net/ to just *.h

SAMA5: FIQs should be disabled along with IRQs on most exeptions in most configuratinons.  arm_decodefiq and arm_decodeirq are mutually exclusive and, hence, can use the same interrupt stack

SAMA5D4:  Add support for secure/FIQ interrupts; SAIC supports need to be be enabled unconditionally