Fix compilation of ssl_tls13_generic.c when memcpy() is a function-like macro

Fixes #8994

Signed-off-by: Tom Cosgrove <tom.cosgrove@arm.com>
diff --git a/library/ssl_tls13_generic.c b/library/ssl_tls13_generic.c
index d448a05..3be6db7 100644
--- a/library/ssl_tls13_generic.c
+++ b/library/ssl_tls13_generic.c
@@ -193,10 +193,12 @@
     idx = 64;
 
     if (from == MBEDTLS_SSL_IS_CLIENT) {
-        memcpy(verify_buffer + idx, MBEDTLS_SSL_TLS1_3_LBL_WITH_LEN(client_cv));
+        memcpy(verify_buffer + idx, mbedtls_ssl_tls13_labels.client_cv,
+               MBEDTLS_SSL_TLS1_3_LBL_LEN(client_cv));
         idx += MBEDTLS_SSL_TLS1_3_LBL_LEN(client_cv);
     } else { /* from == MBEDTLS_SSL_IS_SERVER */
-        memcpy(verify_buffer + idx, MBEDTLS_SSL_TLS1_3_LBL_WITH_LEN(server_cv));
+        memcpy(verify_buffer + idx, mbedtls_ssl_tls13_labels.server_cv,
+               MBEDTLS_SSL_TLS1_3_LBL_LEN(server_cv));
         idx += MBEDTLS_SSL_TLS1_3_LBL_LEN(server_cv);
     }