[media] m5mols: Fix bug in stream on handler

Due to improper condition check streaming start for some pixel
formats was prevent and the s_stream just reatuned -EINVAL.
This fixes regression introduced in commit 5565a2ad
[media] m5mols: Protect driver data with a mutex.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>