Replace __ASSEMBLY__ with compiler-builtin __ASSEMBLER__

NOTE: __ASSEMBLY__ macro is now deprecated in favor of __ASSEMBLER__.

All common C compilers predefine a macro called __ASSEMBLER__ when
preprocessing a .S file. There is no reason for TF-A to define it's own
__ASSEMBLY__ macro for this purpose instead. To unify code with the
export headers (which use __ASSEMBLER__ to avoid one extra dependency),
let's deprecate __ASSEMBLY__ and switch the code base over to the
predefined standard.

Change-Id: Id7d0ec8cf330195da80499c68562b65cb5ab7417
Signed-off-by: Julius Werner <jwerner@chromium.org>
diff --git a/include/lib/runtime_instr.h b/include/lib/runtime_instr.h
index f5a3f13..303f27e 100644
--- a/include/lib/runtime_instr.h
+++ b/include/lib/runtime_instr.h
@@ -17,9 +17,9 @@
 #define RT_INSTR_EXIT_CFLUSH		U(5)
 #define RT_INSTR_TOTAL_IDS		U(6)
 
-#ifndef __ASSEMBLY__
+#ifndef __ASSEMBLER__
 PMF_DECLARE_CAPTURE_TIMESTAMP(rt_instr_svc)
 PMF_DECLARE_GET_TIMESTAMP(rt_instr_svc)
-#endif /* __ASSEMBLY__ */
+#endif /* __ASSEMBLER__ */
 
 #endif /* RUNTIME_INSTR_H */