PTR_ERR_OR_ZERO is designed to replace boiler plate like:

	if (IS_ERR(x))
		return PTR_ERR(x);
	return 0;

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

We have two drivers in the tree which register an "otg" device to
configure the host/peripheral switching. Before introducing a third
driver create a common function for it.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>