media: msm_vidc: Add video driver for video core.

- Adds video encoding and decoding functionality.
- Implements v4l2 interface based driver for interacting
  with userspace modules to perform video encoding and
  decoding.
- Implements kernel API for interacting with kernel
  modules like Wifi display(encoder) and V4L2 based
  DVB(decoder).

Change-Id: Iadb83b60139e659ae7f66e5dc38c46fef52ca99d
Signed-off-by: Vinay Kalia <vkalia@codeaurora.org>
[davidb: only include/linux/videodev2.h]
Signed-off-by: David Brown <davidb@codeaurora.org>