xhci-pci: allow host runtime PM as default for Intel Alpine and Titan Ridge

The xhci controller on Alpine and Titan Ridge keeps the whole thunderbolt
awake if the host controller is not allowed tp sleep.
This is the case even if no USB devices are connected to the host.

Because of this bigger impact, allow runtime pm as default for these xhci
controllers in the driver.

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