ARM: pxa: hx4700: Enable ASIC3 GPIO as a wakeup source

This patch enables the ASIC3 GPIO (12) as a wakeup source:
1. Set the WAKEUP_ON_EDGE_RISE MFP config bits for GPIO12 in
hx4700_pin_config[].
2. Call gpio_set_wake() for GPIO12.

With GPIO12 thus enabled, the mfd/asic3 driver can enable its own GPIOs
as wakeup sources by implementing a irq_set_wake() handler.

Signed-off-by: Paul Parsons <lost.distance@yahoo.com>
Cc: Philipp Zabel <philipp.zabel@gmail.com>
Signed-off-by: Haojian Zhuang <haojian.zhuang@gmail.com>