msm: vidc: set the step field of PROFILE and LEVEL v4l2 controls to 0

Having a non-zero step field for menu items doesn't make any sense.
Moreover, it triggers WARN_ONs inside the v4l2 control framework. Hence
just set it to 0.

Change-Id: I1c20f29c3f3ff7c6c334ced4a0f8c342643c53b2
Signed-off-by: Jayasena Sangaraboina <jsanga@codeaurora.org>