msm: camera: isp: Avoid overflow processing during reset

During device reset, status bits may contain spurious interrupts.
Avoid servicing these spurious interrupts during reset pending. Also,
clear all stats bits before calling reset.

Change-Id: I89e2a1f7f5f97022393ce3b17d07da6d69dd652c
Signed-off-by: Sreesudhan Ramakrish Ramkumar <srramku@codeaurora.org>