Tidy up ARMCE terminology

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/library/aesce.c b/library/aesce.c
index acfac23..84a804a 100644
--- a/library/aesce.c
+++ b/library/aesce.c
@@ -1,5 +1,5 @@
 /*
- *  Arm64 crypto extension support functions
+ *  Armv8-A Cryptographic Extension support functions for Aarch64
  *
  *  Copyright The Mbed TLS Contributors
  *  SPDX-License-Identifier: Apache-2.0