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/libfdt/fdt.h b/include/lib/libfdt/fdt.h
index 74961f9..ef7c86b 100644
--- a/include/lib/libfdt/fdt.h
+++ b/include/lib/libfdt/fdt.h
@@ -52,7 +52,7 @@
  *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef __ASSEMBLY__
+#ifndef __ASSEMBLER__
 
 struct fdt_header {
 	fdt32_t magic;			 /* magic word FDT_MAGIC */
@@ -90,7 +90,7 @@
 	char data[0];
 };
 
-#endif /* !__ASSEMBLY */
+#endif /* !__ASSEMBLER__ */
 
 #define FDT_MAGIC	0xd00dfeed	/* 4: version, 4: total size */
 #define FDT_TAGSIZE	sizeof(fdt32_t)