fix(errata_report): correct typo

Change wrong __arch64__ to __aarch64__.

Change-Id: I750fdb16958e0eadf8aebe24bec0e14488fa4787
Signed-off-by: Yann Gautier <yann.gautier@st.com>
diff --git a/lib/cpus/errata_report.c b/lib/cpus/errata_report.c
index 5d1e3c5..93b2744 100644
--- a/lib/cpus/errata_report.c
+++ b/lib/cpus/errata_report.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2020, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2021, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -19,7 +19,7 @@
 # define BL_STRING	"BL1"
 #elif defined(__aarch64__) && defined(IMAGE_BL31)
 # define BL_STRING	"BL31"
-#elif !defined(__arch64__) && defined(IMAGE_BL32)
+#elif !defined(__aarch64__) && defined(IMAGE_BL32)
 # define BL_STRING	"BL32"
 #elif defined(IMAGE_BL2) && BL2_AT_EL3
 # define BL_STRING "BL2"