PD#141217: add pinctrl & gpio support for m8b
fix gpio irq bugs
TODO: because of limitation of software framework and gpio irq
lines, the ao gpio pins on M8B don't support external irq detect,
and suggest using ee gpio pins to detect.
Change-Id: I933b71104877d97444107d8fba56e3540f94efff
Signed-off-by: Xingyu Chen <xingyu.chen@amlogic.com>