a function pxa_init_irq_set_wake() was introduced, so that
processor specific code could install their own version

code setting PFER and PRER registers within pxa_gpio_irq_type
are removed, and the edge configuration is postponed to the
(*set_wake) and copies the GRER and GFER register, which will
always be set up correctly by pxa_gpio_irq_type()
Signed-off-by: eric miao <eric.y.miao@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>