drm/bridge: Silence error messages upon probe deferral

When -EPROBE_DEFER is returned do not raise an error, but silently return
this error instead. Fixes error like this:
[drm:drm_bridge_attach] *ERROR* failed to attach bridge
/soc@0/bus@30800000/mipi-dsi@30a00000 to encoder None-34: -517
[drm:drm_bridge_attach] *ERROR* failed to attach bridge
/soc@0/bus@30800000/mipi-dsi@30a00000 to encoder None-34: -517

Signed-off-by: Alexander Stein <[e-mail]>
Reviewed-by: Robert Foss <[e-mail]>
Signed-off-by: Robert Foss <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/drm_bridge.c

···
 	bridge->encoder = NULL;
 	list_del(&bridge->chain_node);
 
-	DRM_ERROR("failed to attach bridge %pOF to encoder %s: %d\n",
-		  bridge->of_node, encoder->name, ret);
+	if (ret != -EPROBE_DEFER)
+		DRM_ERROR("failed to attach bridge %pOF to encoder %s: %d\n",
+			  bridge->of_node, encoder->name, ret);
+	else
+		dev_err_probe(encoder->dev->dev, -EPROBE_DEFER,
+			      "failed to attach bridge %pOF to encoder %s\n",
+			      bridge->of_node, encoder->name);
 
 	return ret;
 }