msm: vidc: add input check for hfi q6 function.

The input parameters may be null. This change adds input checks at
function q6_hfi_iface_eventq_read

Signed-off-by: Prasad Nallani <pnalla@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
msm: vidc: Add entry to scale buses for True 4k @ 24 fps
my change6