ARM: OMAP2/3: GPIO: do not attempt to wake-enable

The GPIO IRQ enable/disable path attempts to also enable IRQ wake
support for the parent GPIO bank IRQ as well.  However, since there is
no 'set_wake' hook for the bank IRQs, these calls will always fail.
Also, since the enable will fail on the suspend path, the disable on
the resume path will trigger unbalanced enable/disable warnings.

This was discovered in the suspend/resume path on OMAP3/Beagle using
the gpio-keys driver which disables/re-enables GPIO IRQ wakeups in the
suspend/resume path.

Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>