msm: isp: Fix for few code warnings

Due to uninitialized variables being used warnings
are reported.Made changes to initialize variables
before usage.

CRs-Fixed: 994269
Change-Id: I5288ec5fb21bf2c5b0b0fbf12b8cf9ec5025b8b2
Signed-off-by: Meera Gande <mgande@codeaurora.org>