ACPICA: fix AML mutex re-entrancy

ACPI AML supports "serialized" methods which are protected
by an implicit mutex.  The mutex is re-entrant for that AML thread
to allow recursion.

However, Linux implements notify() by creating a new AML thread.
So for systems where notify() re-enters a serialized method,
deadlock results.

The fix is to use the Linux thread_id as the key to allowing
re-entrancy, not the AML thread pointer.

http://bugzilla.kernel.org/show_bug.cgi?id=5534

Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/include/acpi/acobject.h b/include/acpi/acobject.h
index 04e9735..5206d61 100644
--- a/include/acpi/acobject.h
+++ b/include/acpi/acobject.h
@@ -155,7 +155,7 @@
 struct acpi_object_mutex {
 	ACPI_OBJECT_COMMON_HEADER u8 sync_level;	/* 0-15, specified in Mutex() call */
 	u16 acquisition_depth;	/* Allow multiple Acquires, same thread */
-	struct acpi_thread_state *owner_thread;	/* Current owner of the mutex */
+	acpi_thread_id owner_thread_id;	/* Current owner of the mutex */
 	acpi_mutex os_mutex;	/* Actual OS synchronization object */
 	union acpi_operand_object *prev;	/* Link for list of acquired mutexes */
 	union acpi_operand_object *next;	/* Link for list of acquired mutexes */