Use struct usb_otg members with OTG specific functions instead
of usb_phy members.

Includes fixes from Sascha Hauer.
Signed-off-by: NHeikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: NIgor Grinberg <grinberg@compulab.co.il>
Tested-by: NPhilippe Rétornaz <philippe.retornaz@epfl.ch>
Tested-by: NSascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: NMarek Vasut <marek.vasut@gmail.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>