drm: Make the .mode_fixup() operations mode argument a const pointer

The passed mode must not be modified by the operation, make it const.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/i2c/sil164_drv.c b/drivers/gpu/drm/i2c/sil164_drv.c
index b7d45ab..30b8ae5 100644
--- a/drivers/gpu/drm/i2c/sil164_drv.c
+++ b/drivers/gpu/drm/i2c/sil164_drv.c
@@ -254,7 +254,7 @@
 
 static bool
 sil164_encoder_mode_fixup(struct drm_encoder *encoder,
-			  struct drm_display_mode *mode,
+			  const struct drm_display_mode *mode,
 			  struct drm_display_mode *adjusted_mode)
 {
 	return true;