drm/bridge: synopsys: dw-dp: add bridge before attaching

DRM bridges should be always added to the global bridge list before being
attached.

Reviewed-by: Raphael Gallais-Pou <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Luca Ceresoli <[e-mail]>

drivers/gpu/drm/bridge/synopsys/dw-dp.c

···
 	bridge->type = DRM_MODE_CONNECTOR_DisplayPort;
 	bridge->ycbcr_420_allowed = true;
 
+	devm_drm_bridge_add(dev, bridge);
+
 	dp->aux.dev = dev;
 	dp->aux.drm_dev = encoder->dev;
 	dp->aux.name = dev_name(dev);