[media] v4l2: add VIDIOC_G/S_EDID support to the v4l2 core

Support this ioctl as part of the v4l2 core. Use the new ioctl
name and struct v4l2_edid type in the existing core code.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>