x86: add support for the RDC R-321x SoC

This patch adds support for the RDC R-321x system-on-chip,
also known as R-861x-(G). It uses the generic GPIO API and
has support for the on-chip hardware watchdog.

Build-fix from: Randy Dunlap <randy.dunlap@oracle.com>

Signed-off-by: Florian Fainelli <florian.fainelli@telecomint.eu>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>