android: drivers: Fix build broken by android debugfs fix.

Fix build broken by commit b0bd81a67ae5ced88b ("android: drivers: workaround
debugfs race in binder").

Change-Id: I10c5c0211144a4a1c270dc03f92cf6a1a829e8f8

drivers/staging/android/binder.c

@@ -3603,6 +3603,7 @@ static int binder_transactions_show(struct seq_file *m, void *unused)
 static int binder_proc_show(struct seq_file *m, void *unused)
 {
 	struct binder_proc *itr;
+	struct hlist_node *pos;
 	struct binder_proc *proc = m->private;
 	struct hlist_node *pos;
 	int do_lock = !binder_debug_no_lock;