drm/exynos: Constify function pointer structs

Moves a bunch of junk to .rodata from .data.

 drivers/gpu/drm/exynos/exynosdrm.ko:
-.text                       125792
+.text                       125788
-.rodata                      10972
+.rodata                      11748
-.data                         6720
+.data                         5944

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450178476-26284-19-git-send-email-boris.brezillon@free-electrons.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/exynos/exynos_drm_mic.c b/drivers/gpu/drm/exynos/exynos_drm_mic.c
index 8994eab..4eaef36 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_mic.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_mic.c
@@ -389,7 +389,7 @@
 	mutex_unlock(&mic_mutex);
 }
 
-struct drm_bridge_funcs mic_bridge_funcs = {
+static const struct drm_bridge_funcs mic_bridge_funcs = {
 	.disable = mic_disable,
 	.post_disable = mic_post_disable,
 	.pre_enable = mic_pre_enable,