Add hello retry request count for server

Signed-off-by: XiaokangQian <xiaokang.qian@arm.com>
diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index 020f062..f39f78d 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -585,6 +585,10 @@
     /*!<  Number of Hello Retry Request messages received from the server.  */
     int hello_retry_request_count;
 #endif /* MBEDTLS_SSL_CLI_C */
+#if defined(MBEDTLS_SSL_SRV_C)
+    /*!<  Number of Hello Retry Request messages sent by the server.  */
+    int hello_retry_requests_sent;
+#endif /* MBEDTLS_SSL_SRV_C */
 
 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
     defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)