msm: vidc: Cancel userptr validation during secure decode

Secure decode doesn't need userptr and uses ion fd instead. We were
conducting userptr validation regardless of the decode mode (secure/
unsecure). This forced user to populate userptr with a dummy value
during QBUF in secure mode decode on both output and capture ports
to avoid a userptr validation fail.

CRs-Fixed: 2049213
Change-Id: I0060efb52792201a2634072f648a537ebb02d17c
Signed-off-by: Prabhakar Reddy Krishnappa <prkrishn@codeaurora.org>