Revert "USB: EHCI: support running URB giveback in tasklet context"

This reverts commit 428aac8a81.

This isn't quite ready for 3.12, we need some more EHCI driver changes
that are just now showing up.  So revert this for now, and queue it up
later for 3.13.

Reported-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ehci-q.c

@@ -247,6 +247,8 @@ static int qtd_copy_status (
 
 static void
 ehci_urb_done(struct ehci_hcd *ehci, struct urb *urb, int status)
+__releases(ehci->lock)
+__acquires(ehci->lock)
 {
 	if (usb_pipetype(urb->pipe) == PIPE_INTERRUPT) {
 		/* ... update hc-wide periodic stats */
@@ -272,8 +274,11 @@ ehci_urb_done(struct ehci_hcd *ehci, struct urb *urb, int status)
 		urb->actual_length, urb->transfer_buffer_length);
 #endif
 
+	/* complete() can reenter this HCD */
 	usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
+	spin_unlock (&ehci->lock);
 	usb_hcd_giveback_urb(ehci_to_hcd(ehci), urb, status);
+	spin_lock (&ehci->lock);
 }
 
 static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh);