msm: VPU: Fix Potential Null Pointer Dereferences, Bad Indexing

Changes to prevent possible cases of null pointer dereferencing and
out of bounds array indexing.

Change-Id: I16e319e2e52b259cf4f69d2e93660dbd0b6d36f5
Signed-off-by: Ahmed Abdul-Salam <aabdulsa@codeaurora.org>