genirq: chip: set pending only for edge interrupts

The IRQS_PENDING flag is meant to record an edge interrupt trigger event
when that interrupt is disabled.

When an edge triggered interrupt is enabled, check_irq_resend() retriggers
that irq and resets the flag to zero if set. Note that check_irq_resend()
only does this for edge triggered interrupts.

For level triggered interrupts it is expected that the interrupt remains
active and doesn't need this PENDING flag assistance from software for
re-triggering it.

However, handle_fasteoi_irq flow handler sets the PENDING flag even for
a disabled level interrupt. This causes an adverse effect if that level
interrupt is marked wakeup. The suspend code sees the pending flag on a
wakeup interrupt and aborts suspend whereas check_irq_resend does not reset
it to 0 (as it is a level interrupt). The end result is that the PENDING
flag on this level triggered wakeup interrupt never clears and the system
 keeps aborting suspend.

Fix this by setting IRQS_PENDING flag only for edge interrupts in the
handle_fasteoi_irq.

CRs-Fixed: 314344
Change-Id: I775d40f434f9309fd9672bae372b0f0fb5b91627
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>