ACPI: Add acpi_device_uid() for convenience

Add a nicer way to get the ACPI _UID.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

include/acpi/acpi_bus.h

@@ -252,6 +252,7 @@ struct acpi_device_pnp {
 #define acpi_device_bid(d)	((d)->pnp.bus_id)
 #define acpi_device_adr(d)	((d)->pnp.bus_address)
 const char *acpi_device_hid(struct acpi_device *device);
+#define acpi_device_uid(d)	((d)->pnp.unique_id)
 #define acpi_device_name(d)	((d)->pnp.device_name)
 #define acpi_device_class(d)	((d)->pnp.device_class)