Revert "openpic: Accelerate pending irq search"

Revert "openpic: Accelerate pending irq search"

This reverts commit a9bd83f4c65de0058659ede009fa1a241f379edd.

This counting approach is not robust against setting a bit that
was already set, or clearing a bit that was already clear.  Perhaps
that is considered a bug, but besides the lack of any documentation
for that restriction, it's a pretty unpleasant way for the problem
to manifest itself.

It could be made more robust by testing the current value of the
bit before changing the count, but a later patch speeds up IRQ_check
in all cases, not just when there's nothing pending.  Hopefully that
should be adequate to address performance concerns.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>