usb: ehci: add ehci_port_power interface

The current EHCI implementation is prepared to toggle the
PORT_POWER bit to enable or disable a USB-Port. In some
cases this port power can not be just toggled by the PORT_POWER
bit, and the gpio-regulator is needed to be toggled too.

This patch defines a port power control interface ehci_port_power for
ehci core use, it toggles PORT_POWER bit as well as calls platform
defined .port_power if it is defined.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Acked-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
index eee228a..6f0577b 100644
--- a/drivers/usb/host/ehci.h
+++ b/drivers/usb/host/ehci.h
@@ -859,6 +859,8 @@
 struct ehci_driver_overrides {
 	size_t		extra_priv_size;
 	int		(*reset)(struct usb_hcd *hcd);
+	int		(*port_power)(struct usb_hcd *hcd,
+				int portnum, bool enable);
 };
 
 extern void	ehci_init_driver(struct hc_driver *drv,