ACPI: use more understandable bus_id for ACPI devices

Some of the ACPI devices use the internal fake hids
which are exposed to userspace as devces' bus_id after sysfs conversion.
To make it more friendly, we convert them to more understandable strings.

For those devices w/o PNPids, we use "device:instance_no" as the bus_id
instead of "PNPIDNON:instance_no".

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>