media: v4l: Add definition for the Sunxi tiled NV12 format

This introduces support for the Sunxi tiled NV12 format, where each
component of the YUV frame is divided into macroblocks. Hence, the size
of each plane requires specific alignment. The pixels inside each
macroblock are coded in linear order (line after line from top to
bottom).

This tiled NV12 format is used by the video engine on Allwinner
platforms: it is the default format for decoded frames (and the only
one available in the oldest supported platforms).

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>