[media] v4l2-mediabus: Add pixelcodes for BGR565 formats

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>