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/qemu/qemu_bl2_mem_params_desc.c b/plat/qemu/qemu_bl2_mem_params_desc.c
index ba6a4db..a01f2dc 100644
--- a/plat/qemu/qemu_bl2_mem_params_desc.c
+++ b/plat/qemu/qemu_bl2_mem_params_desc.c
@@ -35,7 +35,7 @@
 	  .next_handoff_image_id = INVALID_IMAGE_ID,
 	},
 #else /* EL3_PAYLOAD_BASE */
-#ifdef AARCH64
+#ifdef __aarch64__
 	/* Fill BL31 related information */
 	{ .image_id = BL31_IMAGE_ID,
 
@@ -59,10 +59,10 @@
 	  .next_handoff_image_id = BL33_IMAGE_ID,
 # endif
 	},
-#endif /* AARCH64 */
+#endif /* __aarch64__ */
 # ifdef QEMU_LOAD_BL32
 
-#ifdef AARCH64
+#ifdef __aarch64__
 #define BL32_EP_ATTRIBS		(SECURE | EXECUTABLE)
 #define BL32_IMG_ATTRIBS	0
 #else