msm: vidc: send video cmd opcode in apr packets to Q6

Q6 expects video command opcode in apr command packets
sent to it,  instead of the individual command id.
Also remove redundant Q6 functions.

Change-Id: I0239f88791af28ee9ba2975d841394e3c6fa9805
Signed-off-by: Arun Menon <avmenon@codeaurora.org>