xhci: Fix sleeping with IRQs disabled in xhci_stop_device()

xhci_stop_device() allocates and issues stop commands for each active endpoint.
This is done with spinlock held and interrupt disabled so we can't sleep during
memory allocation. Use GFP_NOWAIT instead

Regression from commit ddba5cd0
"xhci: Use command structures when queuing commands on the command ring"
for 3.16-rc1

Fixes: ddba5cd0 ("xhci: Use command structures when queuing commands")
Reported-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci-hub.c

@@ -287,7 +287,7 @@ static int xhci_stop_device(struct xhci_hcd *xhci, int slot_id, int suspend)
 		if (virt_dev->eps[i].ring && virt_dev->eps[i].ring->dequeue) {
 			struct xhci_command *command;
 			command = xhci_alloc_command(xhci, false, false,
-						     GFP_NOIO);
+						     GFP_NOWAIT);
 			if (!command) {
 				spin_unlock_irqrestore(&xhci->lock, flags);
 				xhci_free_command(xhci, cmd);