[media] s5p_mfc: Remove unneeded io_modes initialization in s5p_mfc_open()

Remove unneeded io_modes initialization in s5p_mfc_open().
It gets done right below in vdev == dev->vfd_dec conditional.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Acked-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>