Switch AARCH32/AARCH64 to __aarch64__

NOTE: AARCH32/AARCH64 macros are now deprecated in favor of __aarch64__.

All common C compilers pre-define the same macros to signal which
architecture the code is being compiled for: __arm__ for AArch32 (or
earlier versions) and __aarch64__ for AArch64. There's no need for TF-A
to define its own custom macros for this. In order to unify code with
the export headers (which use __aarch64__ to avoid another dependency),
let's deprecate the AARCH32 and AARCH64 macros and switch the code base
over to the pre-defined standard macro. (Since it is somewhat
unintuitive that __arm__ only means AArch32, let's standardize on only
using __aarch64__.)

Change-Id: Ic77de4b052297d77f38fc95f95f65a8ee70cf200
Signed-off-by: Julius Werner <jwerner@chromium.org>
diff --git a/common/bl_common.c b/common/bl_common.c
index 61f031b..a09cd71 100644
--- a/common/bl_common.c
+++ b/common/bl_common.c
@@ -236,7 +236,7 @@
 	PRINT_IMAGE_ARG(1);
 	PRINT_IMAGE_ARG(2);
 	PRINT_IMAGE_ARG(3);
-#ifndef AARCH32
+#ifdef __aarch64__
 	PRINT_IMAGE_ARG(4);
 	PRINT_IMAGE_ARG(5);
 	PRINT_IMAGE_ARG(6);
@@ -245,7 +245,7 @@
 #undef PRINT_IMAGE_ARG
 }
 
-#ifdef AARCH64
+#ifdef __aarch64__
 /*******************************************************************************
  * Handle all possible cases regarding ARMv8.3-PAuth.
  ******************************************************************************/
@@ -293,4 +293,4 @@
 
 #endif /* ENABLE_PAUTH */
 }
-#endif /* AARCH64 */
+#endif /* __aarch64__ */