tinyCrypt: Avoid unused var warning by marking vars as unused
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 16b7f62..d508967 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -4204,6 +4204,7 @@
         mbedtls_ssl_suite_get_key_exchange( ciphersuite_info )
         == MBEDTLS_KEY_EXCHANGE_ECDHE_RSA )
     {
+        ((void) ret);
         if( mbedtls_ssl_ecdh_read_peerkey( ssl, &p, end ) != 0 )
             return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
     }