[ARM] 3584/1: AT91RM9200 GPIO suspend/resume support

Patch from Andrew Victor

This patch adds suspend/resume/set_wake support for the AT91RM9200's
GPIO interrupts.

Original patch from David Brownell.

Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>