usb: xhci_suspend is not stopping the root hub timer for the shared HCD

V2 - Restart polling (which will restart the timer) for the shared
HCD in xhci_resume().

xhci_suspend() will stop the primary HCD's root hub timer, but leaves
the shared HCD's timer running. This change adds stopping of the
shared HCD timer.

Signed-off-by: Al Cooper <alcooperx@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>