V4L/DVB: V4L: SuperH Video Output Unit (VOU) driver

A number of SuperH Mobile SoCs, including sh7724, include a Video Output Unit.
This patch adds a video (V4L2) output driver for it. The driver uses v4l2-subdev
and mediabus APIs to interface to TV encoders.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>