msm: vidc: Add support to set picturetype decode in vidc driver

This commit includes changes to set picturetype decode to firmware.
It also includes changes to update vb2_buffer flags with sync frame.
Includes some other minor fix in driver.

Change-Id: I208ed702aac7383805c4156ec28d71fc47111d6d
Signed-off-by: Sowmya Pandiri <spandiri@codeaurora.org>