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/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index 61d55d3..48e3b76 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -132,7 +132,7 @@
 }
 
 static bool intel_crt_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;