[media] v4l: Add test pattern colour component controls

In many cases the test pattern has selectable values for each colour
component. Implement controls for raw bayer components. Additional controls
should be defined for colour components that are not covered by these
controls.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>