media: vicodec: fix g_selection: either handle crop or compose

The logic of g_selection was wrong: encoders support crop,
decoders support compose, but the code allowed both.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>