tipc: do not use tasklet_disable before tasklet_kill

If tasklet_disable() is called before related tasklet handled,
tasklet_kill will never be finished. tasklet_kill is enough.

Signed-off-by: Xiaotian Feng <[e-mail]>
Cc: Jon Maloy <[e-mail]>
Cc: Allan Stephens <[e-mail]>
Cc: "David S. Miller" <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: David S. Miller <[e-mail]>

net/tipc/handler.c

···
 		return;
 
 	handler_enabled = 0;
-	tasklet_disable(&tipc_tasklet);
 	tasklet_kill(&tipc_tasklet);
 
 	spin_lock_bh(&qitem_lock);