gpio: msm: do not re-enable the interrupt and clear the status

If a gpio interrupt is already enabled, do not re-enable it again and do not
clear the interrupt status.

Before this patch: if an edge interrupt is marked as wakeup, the gpio sys
suspend will enable it.  On resume, the gpio sys resume would clear the
intr_status of the wakeup irq.  Thus, if this particular wakeup irq triggered
and woke us up, we would lose its intr_status before calling the gpio summary
handler.  Now, when the summary handler is finally called, the irq handler for
the wakeup interrupt is never called.

With this change: we are *not* re-enabling the gpio-irq again to make sure that
when the irq framework unmasks all irqs on resume, it does not clear the
intr_status.

Change-Id: Ia5a9c6b00173a56b1abbdd4d4821becb7311d7f6
Signed-off-by: Rohit Vaswani <rvaswani@codeaurora.org>
Signed-off-by: Ajay Dudani <adudani@codeaurora.org>
Signed-off-by: Iliyan Malchev <malchev@google.com>