[media] s5p-mfc: remove unnecessary callbacks

Many version specific functions are not called by common code, so there
is no need to use callbacks. Additionally some of them are not used at all,
so they can be safely removed.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Kamil Debski <k.debski@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>