media: v4l: Add support for V4L2_BUF_TYPE_META_OUTPUT

The V4L2_BUF_TYPE_META_OUTPUT mirrors the V4L2_BUF_TYPE_META_CAPTURE with
the exception that it is an OUTPUT type. The use case for this is to pass
buffers to the device that are not image data but metadata. The formats,
just as the metadata capture formats, are typically device specific and
highly structured.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Tested-by: Tian Shu Qiu <tian.shu.qiu@intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>