wfd: Remove support for V4L2_CID_MPEG_VIDEO_ENCODING control

Instead of using VIDIOC_S_CTRL to set the codec type, V4L clients
are expected to set the codec type as the pixelformat in the
VIDIOC_S_FMT ioctl.  This change is needed as the driver needs to
know the codec when setting the buffer requirements that occurs as part
of the VIDIOC_S_FMT ioctl.

Change-Id: I02b24c2314e429649f4281d5c22133fc166e425b
Signed-off-by: Deva Ramasubramanian <dramasub@codeaurora.org>