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: Kangjie Lu <kjlu@umn.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/strparser/strparser.c b/net/strparser/strparser.c
index da1a676..860dcfb 100644
--- a/net/strparser/strparser.c
+++ b/net/strparser/strparser.c
@@ -550,6 +550,8 @@
 static int __init strp_mod_init(void)
 {
 	strp_wq = create_singlethread_workqueue("kstrp");
+	if (unlikely(!strp_wq))
+		return -ENOMEM;
 
 	return 0;
 }