drm/i915/display: Add a WARN for invalid output range and format

Add a WARN to rule out an invalid output range and format
combination. This is to align the lspcon code with
compute_avi_infoframes.
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201130204738.2443-6-uma.shankar@intel.com

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

@@ -523,6 +523,10 @@ void lspcon_set_infoframes(struct intel_encoder *encoder,
 	else
 		frame.avi.colorspace = HDMI_COLORSPACE_RGB;
 
+	/* nonsense combination */
+	drm_WARN_ON(encoder->base.dev, crtc_state->limited_color_range &&
+		    crtc_state->output_format != INTEL_OUTPUT_FORMAT_RGB);
+
 	if (crtc_state->output_format == INTEL_OUTPUT_FORMAT_RGB) {
 		drm_hdmi_avi_infoframe_quant_range(&frame.avi,
 						   conn_state->connector,