Previously we used the device name in the DSDT, but would
crash upon encountering a duplicate. Also, exposing the
DSDT device name to the user in a patch isn't a good idea,
because it is arbitrary.

After some discussion, we finally decided to use
"PNPID:instance_no" as the bus_id of ACPI devices.

Two attributes for each device are added at the same time,
the full pathname in ACPI namespace and hardware_id if it has.

NOTE:	acpi_bus_id_list is used to keep the information of PNPID
	and instance number of the given PNPID. Loop the
	acpi_bus_id_list to find the instance_no of the	same PNPID
	when register a device. If failed, i.e. we don't have a
	node with this PNPID, allocate one and link it to this list.

NOTE:	Now I don't take the memory free work in charge.
	If necessary, I can add a reference count in
	struct acpi_device_bus_id, and check the reference and
	when unregister a device, i.e. memory is freed when
	the reference count of a given PNPID is 0.

Signed-off-by: Li Shaohua <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>