media: s5p-mfc: Fix display delay control creation

v4l2_ctrl_new_std() fails if the caller provides no 'step' parameter for
integer control, so define it to fix following error:

s5p_mfc_dec_ctrls_setup:1166: Adding control (1) failed

Fixes: c3042bff ("media: s5p-mfc: Use display delay and display enable std controls")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/platform/s5p-mfc/s5p_mfc_dec.c

@@ -172,6 +172,7 @@ static struct mfc_control controls[] = {
 		.type = V4L2_CTRL_TYPE_INTEGER,
 		.minimum = 0,
 		.maximum = 16383,
+		.step = 1,
 		.default_value = 0,
 	},
 	{