msm: vidc: do not modify v4l2 framework quantization controls

Quantization controls are expected to be set by the client and
driver is not supposed to modify the controls to avoid video
encoding usecase failures.

Change-Id: I1daf71e5bffa2c28c500fbf55385a51c924c9916
Signed-off-by: Maheshwar Ajja <majja@codeaurora.org>