usb/xhci: release xhci->lock during turning on/off usb port's acpi power resource...

usb/xhci: release xhci->lock during turning on/off usb port's acpi power resource and checking the existence of port's power resource

When setting usb port's acpi power resource, there will be some xhci hub requests.
This will cause dead lock since xhci->lock has been held before setting acpi power
resource in the xhci_hub_control(). The usb_acpi_power_manageable() function might
fall into sleep so release xhci->lock before invoking it.

Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>