drm/i915/dsb: Skip DSB command buffer setup if we have no LUTs

If we have no LUTs to load there is no point in setting up
the DSB command buffer.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230118163040.29808-9-ville.syrjala@linux.intel.comReviewed-by: NAnimesh Manna <animesh.manna@intel.com>

drivers/gpu/drm/i915/display/intel_color.c

@@ -1383,6 +1383,9 @@ void intel_color_prepare_commit(struct intel_crtc_state *crtc_state)
 	/* FIXME DSB has issues loading LUTs, disable it for now */
 	return;
 
+	if (!crtc_state->pre_csc_lut && !crtc_state->post_csc_lut)
+		return;
+
 	crtc_state->dsb = intel_dsb_prepare(crtc, 1024);
 }