ematch: Fix auto-loading of ematch modules.

In tcf_em_validate(), after calling request_module() to load the
kind-specific module, set em->ops to NULL before returning -EAGAIN, so
that module_put() is not called again by tcf_em_tree_destroy().

Signed-off-by: Ignacy Gawędzki <[e-mail]>
Acked-by: Cong Wang <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/sched/ematch.c

···
 				 * to replay the request.
 				 */
 				module_put(em->ops->owner);
+				em->ops = NULL;
 				err = -EAGAIN;
 			}
 #endif