msm: isp: Fix pingpong mismatch issue

We read pingpong status while handling axi and stats irqs
in tasklet. Due to scheduling delays in tasklet pingpong status is
changing by the time  we read. So, read ping pong status in ISR
and forward it to taslket. This will avoid ping pong mismatch issue
due to scheduler delays.

Change-Id: I42344c76a700a95bc6f5f6a702c15320ad98b7ed
Signed-off-by: Abhishek Kondaveeti <akondave@codeaurora.org>