USB: xhci: Use GFP_ATOMIC under spin_lock

coccinelle check scripts/coccinelle/locks/call_kern.cocci found that
in drivers/usb/host/xhci.c an allocation with GFP_KERNEL is done
with locks held:

xhci_resume
  spin_lock_irq(xhci->lock)
    xhci_setup_msix
      kmalloc(GFP_KERNEL)

Change it to GFP_ATOMIC.
Signed-off-by: David Sterba <dsterba@suse.cz>
CC: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/xhci.c

@@ -240,7 +240,7 @@ static int xhci_setup_msix(struct xhci_hcd *xhci)
 
 	xhci->msix_entries =
 		kmalloc((sizeof(struct msix_entry))*xhci->msix_count,
-				GFP_KERNEL);
+				GFP_ATOMIC);
 	if (!xhci->msix_entries) {
 		xhci_err(xhci, "Failed to allocate MSI-X entries\n");
 		return -ENOMEM;