msm: vidc: adding support of driver editable control values using volatile flags in v4l2 control

Due to various feature constraint and best effort encode/decode, driver needs to update client
updated or default control value.Later these driver updated values are used in programming video
firmware. Hence, we need various controls as volatile

Change-Id: Ied22665addda921b0ef4827fb7a2b1fd47be5bbb
Signed-off-by: Darshana Patil <darshana@codeaurora.org>