[media] s5p-mfc: fix memory leak in s5p_mfc_remove()

s5p_mfc_remove() fails to release encoder and decoder video devices.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Kamil Debski <k.debski@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>