net: strparser: fix a missing check for create_singlethread_workqueue

In case create_singlethread_workqueue fails, the check returns
an error to callers to avoid potential NULL pointer dereferences.
Signed-off-by: NKangjie Lu <kjlu@umn.edu>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/strparser/strparser.c

@@ -550,6 +550,8 @@ EXPORT_SYMBOL_GPL(strp_check_rcv);
 static int __init strp_mod_init(void)
 {
 	strp_wq = create_singlethread_workqueue("kstrp");
+	if (unlikely(!strp_wq))
+		return -ENOMEM;
 
 	return 0;
 }