layers: GH7, Fix bad var names in threading layer

Change-Id: Iabfd7900a934162a425008593ecc0f0b4d56476e
diff --git a/layers/threading.h b/layers/threading.h
index 9617539..8e90f0a 100644
--- a/layers/threading.h
+++ b/layers/threading.h
@@ -34,11 +34,11 @@
 #endif
 
 // Draw State ERROR codes
-typedef enum _THREADING_CHECKER_ERROR {
+enum THREADING_CHECKER_ERROR {
     THREADING_CHECKER_NONE,                // Used for INFO & other non-error messages
     THREADING_CHECKER_MULTIPLE_THREADS,    // Object used simultaneously by multiple threads
     THREADING_CHECKER_SINGLE_THREAD_REUSE, // Object used simultaneously by recursion in single thread
-} THREADING_CHECKER_ERROR;
+};
 
 struct object_use_data {
     loader_platform_thread_id thread;