USB: break apart flush_endpoint and disable_endpoint

This patch (as988) breaks usb_hcd_endpoint_disable() apart into two
routines.  The first, usb_hcd_flush_endpoint() does the -ESHUTDOWN
unlinking of all URBs in the endpoint's queue and waits for them to
complete.  The second, usb_hcd_disable_endpoint() -- renamed for
better grammatical style -- merely calls the HCD's endpoint_disable
method.  The changeover is easy because the routine currently has only
one caller.

This separation of function will be exploited in the following patch:
When a device is suspended, the core will be able to cancel all
outstanding URBs for that device while leaving the HCD's
endpoint-related data structures intact for later.

As an added benefit, HCDs no longer need to check for existing URBs in
their endpoint_disable methods.  It is now guaranteed that there will
be none.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/core/hcd.h b/drivers/usb/core/hcd.h
index 0fc7b95..1396141 100644
--- a/drivers/usb/core/hcd.h
+++ b/drivers/usb/core/hcd.h
@@ -219,7 +219,9 @@
 extern int usb_hcd_unlink_urb (struct urb *urb, int status);
 extern void usb_hcd_giveback_urb(struct usb_hcd *hcd, struct urb *urb,
 		int status);
-extern void usb_hcd_endpoint_disable (struct usb_device *udev,
+extern void usb_hcd_flush_endpoint(struct usb_device *udev,
+		struct usb_host_endpoint *ep);
+extern void usb_hcd_disable_endpoint(struct usb_device *udev,
 		struct usb_host_endpoint *ep);
 extern int usb_hcd_get_frame_number (struct usb_device *udev);