xhci: turn off port power in shutdown

If ports are not turned off in shutdown then runtime suspended
self-powered USB devices may survive in U3 link state over S5.

During subsequent boot, if firmware sends an IPC command to program
the port in DISCONNECT state, it will time out, causing significant
delay in the boot time.

Turning off roothub port power is also recommended in xhci
specification 4.19.4 "Port Power" in the additional note.

Cc: stable@vger.kernel.org
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20220623111945.1557702-3-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>