media: v4l2-ctrls: add __v4l2_ctrl_s_ctrl_compound()

Rather than creating new compound control helpers for each new
type, create one generic function and just create defines on
top.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Tested-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>