msm: camera: Fix crash in camera on 8660

The ackpending flag check is not valid while processing cs
stats irq which is causing an additional read to the ping pong
status register and resulting in crash of the device.

Change-Id: I8dab122ab2cd93718f2a90f493822bddd299b457
Signed-off-by: Lakshmi Narayana Kalavala <lkalaval@codeaurora.org>