v4l: Add new mode for in-band video header in all I-frames

V4L clients should be able to specify the video header to be present
in all I-frame (as it is common in many broadcasting scenarios).  By
specifying this mode, V4L clients will receive sps/pps information
prepended to all I-frames.

Change-Id: Ia93b1d0a59b8d1abf13d1bdb8de494f13ebe1c95
Signed-off-by: Deva Ramasubramanian <dramasub@codeaurora.org>
Signed-off-by: David Brown <davidb@codeaurora.org>