drm/msm: Use drm_attach_bridge() to attach a bridge to an encoder

This is part of our attempt to make the bridge chain a double-linked
list based on the generic list helpers. In order to do that, we must
patch all drivers manipulating the encoder->bridge field directly.
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sean Paul <sean@poorly.run>
Link: https://patchwork.freedesktop.org/patch/msgid/20190826152649.13820-9-boris.brezillon@collabora.com

drivers/gpu/drm/msm/edp/edp.c

@@ -178,7 +178,9 @@ int msm_edp_modeset_init(struct msm_edp *edp, struct drm_device *dev,
 		goto fail;
 	}
 
-	encoder->bridge = edp->bridge;
+	ret = drm_bridge_attach(encoder, edp->bridge, NULL);
+	if (ret)
+		goto fail;
 
 	priv->bridges[priv->num_bridges++]       = edp->bridge;
 	priv->connectors[priv->num_connectors++] = edp->connector;

drivers/gpu/drm/msm/hdmi/hdmi.c

@@ -327,7 +327,9 @@ int msm_hdmi_modeset_init(struct hdmi *hdmi,
 		goto fail;
 	}
 
-	encoder->bridge = hdmi->bridge;
+	ret = drm_bridge_attach(encoder, hdmi->bridge, NULL);
+	if (ret)
+		goto fail;
 
 	priv->bridges[priv->num_bridges++]       = hdmi->bridge;
 	priv->connectors[priv->num_connectors++] = hdmi->connector;