[media] videodev2.h/v4l2-dv-timings.h: add V4L2_DV_FL_IS_CE_VIDEO flag

In the past the V4L2_DV_BT_STD_CEA861 standard bit was used to
determine whether the format is a CE (Consumer Electronics) format
or not. However, the 640x480p59.94 format is part of the CEA-861
standard, but it is *not* a CE video format.

Add a new flag to make this explicit. This information is needed
in order to determine the default R'G'B' encoding for the format:
for CE video this is limited range (16-235) instead of full range
(0-255).

The header with all the timings has been updated with this new
flag.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Martin Bugge <marbugge@cisco.com>
Cc: Mats Randgaard <mats.randgaard@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>