Rename MBEDTLS_ARCH_IS_ARMV8 to MBEDTLS_ARCH_IS_ARMV8_A

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/include/mbedtls/check_config.h b/include/mbedtls/check_config.h
index 0dba0a8..eac2266 100644
--- a/include/mbedtls/check_config.h
+++ b/include/mbedtls/check_config.h
@@ -865,7 +865,7 @@
 
 #endif
 
-#if defined(MBEDTLS_SHA256_USE_ARMV8_CRYPTO_ONLY) && !defined(MBEDTLS_ARCH_IS_ARMV8)
+#if defined(MBEDTLS_SHA256_USE_ARMV8_CRYPTO_ONLY) && !defined(MBEDTLS_ARCH_IS_ARMV8_A)
 #error "MBEDTLS_SHA256_USE_ARMV8_CRYPTO_ONLY defined on non-Armv8-A system"
 #endif