gpio/omap: enable irq at the end of all configuration in restore

Setup the interrupt enable registers only after we have configured the
required edge and required configurations, not before, to prevent
spurious events as part of restore routine.

Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Tarun Kanti DebBarma <tarun.kanti@ti.com>
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>