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/utils_def.h b/include/lib/utils_def.h
index 41f71e8..7098bac 100644
--- a/include/lib/utils_def.h
+++ b/include/lib/utils_def.h
@@ -32,7 +32,7 @@
  * position @h. For example
  * GENMASK_64(39, 21) gives us the 64bit vector 0x000000ffffe00000.
  */
-#if defined(__LINKER__) || defined(__ASSEMBLY__)
+#if defined(__LINKER__) || defined(__ASSEMBLER__)
 #define GENMASK_32(h, l) \
 	(((0xFFFFFFFF) << (l)) & (0xFFFFFFFF >> (32 - 1 - (h))))