msm: vidc: Treat use-ltr control as bitmask

Treat use-ltr control as a bitmask instead of
an index. This change aligns driver behavior with
framework.

Change-Id: I36dfd732f5729a629970f8a731cffadd59a454c4
Signed-off-by: Saurabh Kothawade <skothawa@codeaurora.org>