[media] m5mols: Do not reset the configured pixel format when unexpected

Initialize default pixel format in driver probe() rather than in
s_power handler. This also prevents resetting the configuration
applied before the device was powered on.

Acked-by: HeungJun Kim <riverful.kim@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>