ACPI: Allow ACPI binding with USB-3.0 hub

A USB port's position and connectability can't be identified on some boards
via USB hub registers. ACPI _UPC and _PLD can help to resolve this issue
and so it is necessary to bind USB with ACPI. This patch is to allow ACPI
binding with USB-3.0 hub.

Current ACPI only can bind one struct-device to one ACPI device node.
This can not work with USB-3.0 hub, because the USB-3.0 hub has two logical
devices. Each works for USB-2.0 and USB-3.0 devices. In the Linux USB subsystem,
those two logical hubs are treated as two seperate devices that have two struct
devices. But in the ACPI DSDT, these two logical hubs share one ACPI device
node. So there is a requirement to bind multi struct-devices to one ACPI
device node. This patch is to resolve such problem.

Following is the ACPI device nodes' description under xhci hcd.

Device (XHC)
            Device (RHUB)
                Device (HSP1)
                Device (HSP2)
                Device (HSP3)
                Device (HSP4)
                Device (SSP1)
                Device (SSP2)
                Device (SSP3)
                Device (SSP4)

Topology in the Linux

	device XHC
	   USB-2.0 logical hub    USB-3.0 logical hub
		HSP1			SSP1
		HSP2			SSP2
		HSP3			SSP3
		HSP4			SSP4

This patch also modifies the output of /proc/acpi/wakeup. One ACPI node
can be associated with multiple devices:

XHC		S4	*enabled	pci:0000:00:14.0
RHUB	S0	disabled	usb:usb1
			disabled	usb:usb2

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