am,x86-nemu,asye: enable interrupt in user prog

am/arch/x86-nemu/src/asye.c

@@ -66,7 +66,7 @@ _RegSet *_make(_Area stack, void *entry, void *arg) {
   r->esp = (uintptr_t)r;
   r->cs = 0x8;
   r->eip = (uintptr_t)entry;
-  r->eflags = 0;
+  r->eflags = 0x2 | FL_IF;
   return r;
 }
 
@@ -75,11 +75,5 @@ void _trap() {
 }
 
 int _istatus(int enable) {
-  int ret = (get_efl() & FL_IF) != 0;
-  if (enable) {
-    sti();
-  } else {
-    cli();
-  }
-  return ret;
+  return 0;
 }