USB: OHCI: don't look at the root hub to get the number of ports

This patch (as1371) fixes a small bug in ohci-hcd.  The HCD already
knows how many ports the controller has; there's no need to go looking
at the root hub's usb_device structure to find out.  Especially since
the root hub's maxchild value is set correctly only while the root hub
is bound to the hub driver.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/ohci-hub.c

@@ -697,7 +697,7 @@ static int ohci_hub_control (
 	u16		wLength
 ) {
 	struct ohci_hcd	*ohci = hcd_to_ohci (hcd);
-	int		ports = hcd_to_bus (hcd)->root_hub->maxchild;
+	int		ports = ohci->num_ports;
 	u32		temp;
 	int		retval = 0;