util: Remove usage of USE_ELF_TLS in u_thread.h

Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17213>

src/util/u_thread.h

@@ -78,7 +78,6 @@
  * still want to use normal TLS (which involves a function call, but not the
  * expensive pthread_getspecific() or its equivalent).
  */
-#ifdef USE_ELF_TLS
 #if DETECT_OS_APPLE
 /* Apple Clang emits wrappers when using thread_local that break module linkage,
  * but not with __thread
@@ -90,7 +89,6 @@
 #else
 #define __THREAD_INITIAL_EXEC thread_local
 #endif
-#endif
 
 static inline int
 util_get_current_cpu(void)