py: Eliminate some cases which trigger unused parameter warnings.
diff --git a/py/objstr.c b/py/objstr.c
index ed61d17..9982322 100644
--- a/py/objstr.c
+++ b/py/objstr.c
@@ -172,11 +172,13 @@
 STATIC mp_obj_t bytes_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
     (void)type_in;
 
-#if MICROPY_CPYTHON_COMPAT
+    #if MICROPY_CPYTHON_COMPAT
     if (n_kw != 0) {
         mp_arg_error_unimpl_kw();
     }
-#endif
+    #else
+    (void)n_kw;
+    #endif
 
     if (n_args == 0) {
         return mp_const_empty_bytes;