[media] s5p-mfc: Fix encoder control 15 issue

mfc-encoder is not working in the latest kernel giving the
erorr "Adding control (15) failed". Adding the missing step
parameter in this control to fix the issue.
Signed-off-by: NArun Kumar K <arun.kk@samsung.com>
Signed-off-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/platform/s5p-mfc/s5p_mfc_enc.c

@@ -232,6 +232,7 @@ static struct mfc_control controls[] = {
 		.minimum = 0,
 		.maximum = 1,
 		.default_value = 0,
+		.step = 1,
 		.menu_skip_mask = 0,
 	},
 	{