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/plat/arm/common/arm_gicv3.c b/plat/arm/common/arm_gicv3.c
index 93bebf3..7f4957f 100644
--- a/plat/arm/common/arm_gicv3.c
+++ b/plat/arm/common/arm_gicv3.c
@@ -83,8 +83,8 @@
 	 * can use GIC system registers to manage interrupts and does
 	 * not need GIC interface base addresses to be configured.
 	 */
-#if (defined(AARCH32) && defined(IMAGE_BL32)) || \
-	(defined(IMAGE_BL31) && !defined(AARCH32))
+#if (!defined(__aarch64__) && defined(IMAGE_BL32)) || \
+	(defined(__aarch64__) && defined(IMAGE_BL31))
 	gicv3_driver_init(&arm_gic_data);
 #endif
 }