Add the cpu.c and dev.c and modify w90p910 platform
to apply to use the common API(provided by cpu.c and dev.c)
at the same time, I renamed all w90x900 to nuc900 in every
c file of w90x900 platform and touchscreen's driver name.
Signed-off-by: NWan ZongShun <mcuos.com@gmail.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add gpio api for w90p910 platform.
Signed-off-by: NWan ZongShun <mcuos.com@gmail.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>