As PControl G20 is a carrier board for the Stamp9G20 SoM, some code can
be shared. Therefore board-stamp9g20.c is refactored to allow reusing the
SoM initialization and board-pcontrol-g20.c is modified to use it.
Signed-off-by: NChristian Glindkamp <christian.glindkamp@taskit.de>
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>

Board is a carrier board for Stamp9G20, with additional peripherals
for a building automation system
Signed-off-by: NPeter Gsellmann <pgsellmann@portner-elektronik.at>
[nicolas.ferre@atmel.com: remove machine_desc.io_pg_offst and .phys_io]
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>