rt6_probe_deferred: Do not depend on struct ordering

rt6_probe allocates a struct __rt6_probe_work and schedules a work handler rt6_probe_deferred.
But rt6_probe_deferred kfree's the struct work_struct instead of struct __rt6_probe_work.
This works, because struct work_struct is the first element of struct __rt6_probe_work.

Change it to kfree struct __rt6_probe_work to not implicitly depend on
struct work_struct being the first element.

This does not affect the generated code.
Signed-off-by: Michael Buesch <m@bues.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/route.c

@@ -499,7 +499,7 @@ static void rt6_probe_deferred(struct work_struct *w)
 	addrconf_addr_solict_mult(&work->target, &mcaddr);
 	ndisc_send_ns(work->dev, NULL, &work->target, &mcaddr, NULL);
 	dev_put(work->dev);
-	kfree(w);
+	kfree(work);
 }
 
 static void rt6_probe(struct rt6_info *rt)