drm/i915: Constify adjusted_mode

Make adjusted_mode const whereever we don't have to modify it. This only
covers cases when we have a local adjusted_mode variable, and doesn't
make any difference for cases where we just dereference
pipe_config->adjusted_mode.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Mika Kahola <mika.kahola@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/dvo_tfp410.c

@@ -222,8 +222,8 @@ static enum drm_mode_status tfp410_mode_valid(struct intel_dvo_device *dvo,
 }
 
 static void tfp410_mode_set(struct intel_dvo_device *dvo,
-			    struct drm_display_mode *mode,
-			    struct drm_display_mode *adjusted_mode)
+			    const struct drm_display_mode *mode,
+			    const struct drm_display_mode *adjusted_mode)
 {
 	/* As long as the basics are set up, since we don't have clock dependencies
 	* in the mode setup, we can just leave the registers alone and everything