drm/exynos: Constify exynos_drm_crtc_ops

The Exynos DRM code does not modify the ops provided by CRTC driver in
exynos_drm_crtc_create() call.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
diff --git a/drivers/gpu/drm/exynos/exynos_mixer.c b/drivers/gpu/drm/exynos/exynos_mixer.c
index 1a07fdd..31c1793 100644
--- a/drivers/gpu/drm/exynos/exynos_mixer.c
+++ b/drivers/gpu/drm/exynos/exynos_mixer.c
@@ -1129,7 +1129,7 @@
 	return -EINVAL;
 }
 
-static struct exynos_drm_crtc_ops mixer_crtc_ops = {
+static const struct exynos_drm_crtc_ops mixer_crtc_ops = {
 	.dpms			= mixer_dpms,
 	.enable_vblank		= mixer_enable_vblank,
 	.disable_vblank		= mixer_disable_vblank,