sh: mach-x3proto: gpio-keys support.
sh: mach-x3proto: gpio-keys support.

This adds gpio-keys mappings for the button matrix on the baseboard,
now that we have support for the pin controller.

Signed-off-by: Paul Mundt <38b52dbb5f0b63d149982b6c5de788ec93a89032@linux-sh.org>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs