Introduce and use MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED

Introduce and use
MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED to
guard TLS code (both TLS 1.2 and 1.3) specific
to handshakes involving certificates.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/library/ssl_client.c b/library/ssl_client.c
index 543c821..01f1b68 100644
--- a/library/ssl_client.c
+++ b/library/ssl_client.c
@@ -608,7 +608,7 @@
     }
 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
 
-#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
+#if defined(MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED)
     if(
 #if defined(MBEDTLS_SSL_PROTO_TLS1_3)
         ( propose_tls13 && mbedtls_ssl_conf_tls13_ephemeral_enabled( ssl ) ) ||
@@ -623,7 +623,7 @@
             return( ret );
         p += output_len;
     }
-#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
+#endif /* MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED */
 
 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
     if( propose_tls12 )