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/common/runtime_svc.h b/include/common/runtime_svc.h
index e5e36c7..3b0a224 100644
--- a/include/common/runtime_svc.h
+++ b/include/common/runtime_svc.h
@@ -39,7 +39,7 @@
  */
 #define MAX_RT_SVCS		U(128)
 
-#ifndef __ASSEMBLY__
+#ifndef __ASSEMBLER__
 
 /* Prototype for runtime service initializing function */
 typedef int32_t (*rt_svc_init_t)(void);
@@ -134,5 +134,5 @@
 
 extern uint8_t rt_svc_descs_indices[MAX_RT_SVCS];
 
-#endif /*__ASSEMBLY__*/
+#endif /*__ASSEMBLER__*/
 #endif /* RUNTIME_SVC_H */