msm: vidc: NULL terminate devicetree match table

Without NULL termination, of_dev_lookup() can run
off the end of the array and looking at invalid data.

Change-Id: Ib7d8b3afdc76d3f196d620d47eb77d4e0bc74d53
CRs-fixed: 582111
Signed-off-by: Sachin Shah <sachins@codeaurora.org>