drm/vc4: fix infinite EPROBE_DEFER loop

`vc4_hdmi_audio_init` calls `devm_snd_dmaengine_pcm_register` which may
return EPROBE_DEFER. Calling `drm_connector_hdmi_audio_init` adds a
child device. The driver model docs[1] state that adding a child device
prior to returning EPROBE_DEFER may result in an infinite loop.

[1] https://www.kernel.org/doc/html/v6.14/driver-api/driver-model/driver.html

Fixes: 9640f14 ("drm/vc4: hdmi: switch to using generic HDMI Codec infrastructure")
Signed-off-by: Gabriel Dalimonte <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Maxime Ripard <[email protected]>

Author: Mornix

drivers/gpu/drm/vc4/vc4_hdmi.c

@@ -560,12 +560,6 @@ static int vc4_hdmi_connector_init(struct drm_device *dev,
 	if (ret)
 		return ret;
 
-	ret = drm_connector_hdmi_audio_init(connector, dev->dev,
-					    &vc4_hdmi_audio_funcs,
-					    8, false, -1);
-	if (ret)
-		return ret;
-
 	drm_connector_helper_add(connector, &vc4_hdmi_connector_helper_funcs);
 
 	/*
@@ -2291,6 +2285,12 @@ static int vc4_hdmi_audio_init(struct vc4_hdmi *vc4_hdmi)
 		return ret;
 	}
 
+	ret = drm_connector_hdmi_audio_init(&vc4_hdmi->connector, dev,
+					    &vc4_hdmi_audio_funcs, 8, false,
+					    -1);
+	if (ret)
+		return ret;
+
 	dai_link->cpus		= &vc4_hdmi->audio.cpu;
 	dai_link->codecs	= &vc4_hdmi->audio.codec;
 	dai_link->platforms	= &vc4_hdmi->audio.platform;