msm: camera: common: va_end should follow va_start

Each  invocation  of  va_start() must be matched by a corresponding
invocation of va_end() in the same function.

CRs-Fixed: 2549155
Change-Id: I6a3214ce863c4af0425d061184cfa44682f89545
Signed-off-by: Trishansh Bhardwaj <tbhardwa@codeaurora.org>