USB: EHCI: Fix build warning in xilinx ehci driver

This fixes the following warning:
In file included from drivers/usb/host/ehci-hcd.c:1246:0:
drivers/usb/host/ehci-xilinx-of.c:293:2: warning: initialization from incompatible pointer type [enabled by default]
drivers/usb/host/ehci-xilinx-of.c:293:2: warning: (near initialization for 'ehci_hcd_xilinx_of_driver.shutdown') [enabled by default]
Signed-off-by: NHerton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ehci-xilinx-of.c

@@ -270,14 +270,12 @@ static int ehci_hcd_xilinx_of_remove(struct platform_device *op)
  *
  * Properly shutdown the hcd, call driver's shutdown routine.
  */
-static int ehci_hcd_xilinx_of_shutdown(struct platform_device *op)
+static void ehci_hcd_xilinx_of_shutdown(struct platform_device *op)
 {
 	struct usb_hcd *hcd = dev_get_drvdata(&op->dev);
 
 	if (hcd->driver->shutdown)
 		hcd->driver->shutdown(hcd);
-
-	return 0;
 }