[media] sh-vou: let sh_vou_s_fmt_vid_out call sh_vou_try_fmt_vid_out

This ensures that both do the same checks, and simplifies s_fmt_vid_out
a bit.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>