[media] v4l2: use new V4L2_DV_BT_BLANKING/FRAME defines

[media] v4l2: use new V4L2_DV_BT_BLANKING/FRAME defines

Use the new blanking and frame size defines. This also fixed a bug in
these drivers: they assumed that the height for interlaced formats was
the field height, however height is the frame height. So the height
for a field is actually bt->height / 2.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>