media: vicodec: selection api should only check single buffer types

The selection api should check only single buffer types
because multiplanar types are converted to
single in drivers/media/v4l2-core/v4l2-ioctl.c

Signed-off-by: Dafna Hirschfeld <dafna3@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>