notifier: switch to QLIST

Notifiers do not need to access both ends of the list, and using
a QLIST also simplifies the API.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/input.c b/input.c
index 9ade63f..b618ea4 100644
--- a/input.c
+++ b/input.c
@@ -268,5 +268,5 @@
 
 void qemu_remove_mouse_mode_change_notifier(Notifier *notify)
 {
-    notifier_list_remove(&mouse_mode_notifiers, notify);
+    notifier_remove(notify);
 }