msm: isp: Clear irq status if irq is set again with same value

Sometimes same irq is received even after clearing irq.
make sure irq status is rest by clearing the irq again.

Change-Id: Ib5355a4b9952fa7f02d1dea69b5fb767928e4b9f
Signed-off-by: Srikanth Uyyala <suyyala@codeaurora.org>