Fix issue in checking in writing extensions

Fix issue in checking if server received
record size limit extension.

Signed-off-by: Waleed Elmelegy <waleed.elmelegy@arm.com>
diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index 36d1c05..227d287 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -2500,9 +2500,6 @@
     size_t extensions_len = 0;
     unsigned char *p_extensions_len;
     size_t output_len;
-#if defined(MBEDTLS_SSL_RECORD_SIZE_LIMIT)
-    uint32_t record_size_extension_mask;
-#endif
 
     *out_len = 0;
 
@@ -2534,8 +2531,7 @@
 #endif /* MBEDTLS_SSL_EARLY_DATA */
 
 #if defined(MBEDTLS_SSL_RECORD_SIZE_LIMIT)
-    record_size_extension_mask = mbedtls_ssl_get_extension_mask(MBEDTLS_TLS_EXT_RECORD_SIZE_LIMIT);
-    if (ssl->handshake->received_extensions | record_size_extension_mask) {
+    if (ssl->handshake->received_extensions & MBEDTLS_SSL_EXT_MASK(RECORD_SIZE_LIMIT)) {
         ret = mbedtls_ssl_tls13_write_record_size_limit_ext(
             ssl, p, end, &output_len);
         if (ret != 0) {