V4L/DVB (13571): v4l: Adding Digital Video Timings APIs

V4L/DVB (13571): v4l: Adding Digital Video Timings APIs

This adds the above APIs to the v4l2 core. This is based on version v1.2
of the RFC titled "V4L - Support for video timings at the input/output interface"
Following new ioctls are added:-

        - VIDIOC_ENUM_DV_PRESETS
        - VIDIOC_S_DV_PRESET
        - VIDIOC_G_DV_PRESET
        - VIDIOC_QUERY_DV_PRESET
        - VIDIOC_S_DV_TIMINGS
        - VIDIOC_G_DV_TIMINGS

Please refer to the RFC for the details. This code was tested using vpfe
capture driver on TI's DM365. Following is the test configuration used :-

Blu-Ray HD DVD source -> TVP7002 -> DM365 (VPFE) ->DDR

A draft version of the TVP7002 driver (currently being reviewed in the mailing
list) was used that supports V4L2_DV_1080I60 & V4L2_DV_720P60 presets.

A loopback video capture application was used for testing these APIs. This calls
following IOCTLS :-

 -  verify the new v4l2_input capabilities flag added
 -  Enumerate available presets using VIDIOC_ENUM_DV_PRESETS
 -  Set one of the supported preset using VIDIOC_S_DV_PRESET
 -  Get current preset using VIDIOC_G_DV_PRESET
 -  Detect current preset using VIDIOC_QUERY_DV_PRESET
 -  Using stub functions in tvp7002, verify VIDIOC_S_DV_TIMINGS
    and VIDIOC_G_DV_TIMINGS ioctls are received at the sub device.
 -  Tested on 64bit platform by Hans Verkuil

Signed-off-by: Muralidharan Karicheri <m-karicheri2@ti.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Reviewed-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>