[media] s5p_mfc_opr_v6: remove address space removal warnings

Smatch still has 3 warnings for s5p_mfc_opr_v6:

drivers/media/platform/s5p-mfc/s5p_mfc_opr_v6.c:2028:18: warning: cast removes address space of expression
drivers/media/platform/s5p-mfc/s5p_mfc_opr_v6.c:2034:18: warning: cast removes address space of expression
drivers/media/platform/s5p-mfc/s5p_mfc_opr_v6.c:2040:18: warning: cast removes address space of expression

Remove them.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>