The intent was to test whether the flag was set.
This patch should be backported to stable kernels as old as 3.0, since
it fixes a bug in commit 
e95829f474f0db3a4d940cae1423783edd966027 "xhci:
Switch PPT ports to EHCI on shutdown.", which was marked for stable.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org
 
 {
        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
 
-       if (xhci->quirks && XHCI_SPURIOUS_REBOOT)
+       if (xhci->quirks & XHCI_SPURIOUS_REBOOT)
                usb_disable_xhci_ports(to_pci_dev(hcd->self.controller));
 
        spin_lock_irq(&xhci->lock);