drm/amdgpu: Remove pointless on stack mode copies

These on stack copies of the modes appear to be pointless.
Just look at the originals directly.

Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Leo Li <sunpeng.li@amd.com>
Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: amd-gfx@lists.freedesktop.org
Cc: Nikola Cornij <nikola.cornij@amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -10181,27 +10181,27 @@ static bool
 is_timing_unchanged_for_freesync(struct drm_crtc_state *old_crtc_state,
 				 struct drm_crtc_state *new_crtc_state)
 {
-	struct drm_display_mode old_mode, new_mode;
+	const struct drm_display_mode *old_mode, *new_mode;
 
 	if (!old_crtc_state || !new_crtc_state)
 		return false;
 
-	old_mode = old_crtc_state->mode;
-	new_mode = new_crtc_state->mode;
-
-	if (old_mode.clock       == new_mode.clock &&
-	    old_mode.hdisplay    == new_mode.hdisplay &&
-	    old_mode.vdisplay    == new_mode.vdisplay &&
-	    old_mode.htotal      == new_mode.htotal &&
-	    old_mode.vtotal      != new_mode.vtotal &&
-	    old_mode.hsync_start == new_mode.hsync_start &&
-	    old_mode.vsync_start != new_mode.vsync_start &&
-	    old_mode.hsync_end   == new_mode.hsync_end &&
-	    old_mode.vsync_end   != new_mode.vsync_end &&
-	    old_mode.hskew       == new_mode.hskew &&
-	    old_mode.vscan       == new_mode.vscan &&
-	    (old_mode.vsync_end - old_mode.vsync_start) ==
-	    (new_mode.vsync_end - new_mode.vsync_start))
+	old_mode = &old_crtc_state->mode;
+	new_mode = &new_crtc_state->mode;
+
+	if (old_mode->clock       == new_mode->clock &&
+	    old_mode->hdisplay    == new_mode->hdisplay &&
+	    old_mode->vdisplay    == new_mode->vdisplay &&
+	    old_mode->htotal      == new_mode->htotal &&
+	    old_mode->vtotal      != new_mode->vtotal &&
+	    old_mode->hsync_start == new_mode->hsync_start &&
+	    old_mode->vsync_start != new_mode->vsync_start &&
+	    old_mode->hsync_end   == new_mode->hsync_end &&
+	    old_mode->vsync_end   != new_mode->vsync_end &&
+	    old_mode->hskew       == new_mode->hskew &&
+	    old_mode->vscan       == new_mode->vscan &&
+	    (old_mode->vsync_end - old_mode->vsync_start) ==
+	    (new_mode->vsync_end - new_mode->vsync_start))
 		return true;
 
 	return false;