msm: vidc: Add NULL check for bus vote data allocation

While allocating bus vote data, add NULL check to make sure that
failure of malloc is handled properly.

CRs-Fixed: 2115630
Change-Id: If9cf41003d03ccc067f2c2fda324e1e5546e677a
Signed-off-by: Praneeth Paladugu <ppaladug@codeaurora.org>