drm/bridge: anx6345: don't print error message if regulator is not ready

We don't want to print scary message if devm_regulator_get() returns
-EPROBE_DEFER

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20200226081011.1347245-3-anarsoul@gmail.com