patch 8.1.1800: function call functions have too many arguments

Problem:    Function call functions have too many arguments.
Solution:   Pass values in a funcexe_T struct.
diff --git a/src/ex_cmds2.c b/src/ex_cmds2.c
index a8be96d..c44ac8d 100644
--- a/src/ex_cmds2.c
+++ b/src/ex_cmds2.c
@@ -110,15 +110,13 @@
 timer_callback(timer_T *timer)
 {
     typval_T	rettv;
-    int		dummy;
     typval_T	argv[2];
 
     argv[0].v_type = VAR_NUMBER;
     argv[0].vval.v_number = (varnumber_T)timer->tr_id;
     argv[1].v_type = VAR_UNKNOWN;
 
-    call_callback(&timer->tr_callback, -1,
-			&rettv, 1, argv, NULL, 0L, 0L, &dummy, TRUE, NULL);
+    call_callback(&timer->tr_callback, -1, &rettv, 1, argv);
     clear_tv(&rettv);
 }