drm/radeon: Use correct value for unknown audio/video latency

Valid values are 1 to 251 for 0 to 500 ms latency, 0 for unknown
and 255 for audio/video unsupported by sink, according to HDMI 1.3 spec.
Also matches Radeon HDA verb 0xf7b documentation.

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/dce6_afmt.c

@@ -136,13 +136,13 @@ void dce6_afmt_write_latency_fields(struct drm_encoder *encoder,
 			tmp = VIDEO_LIPSYNC(connector->video_latency[1]) |
 				AUDIO_LIPSYNC(connector->audio_latency[1]);
 		else
-			tmp = VIDEO_LIPSYNC(255) | AUDIO_LIPSYNC(255);
+			tmp = VIDEO_LIPSYNC(0) | AUDIO_LIPSYNC(0);
 	} else {
 		if (connector->latency_present[0])
 			tmp = VIDEO_LIPSYNC(connector->video_latency[0]) |
 				AUDIO_LIPSYNC(connector->audio_latency[0]);
 		else
-			tmp = VIDEO_LIPSYNC(255) | AUDIO_LIPSYNC(255);
+			tmp = VIDEO_LIPSYNC(0) | AUDIO_LIPSYNC(0);
 	}
 	WREG32_ENDPOINT(offset, AZ_F0_CODEC_PIN_CONTROL_RESPONSE_LIPSYNC, tmp);
 }