audit: Remove leftover reference to the audit_tasklet

This was replaced with a kauditd_wait kthread long ago,
back in:

     b7d11258 (AUDIT: Send netlink messages from a separate kernel thread)

Update the stale comment.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paul Moore <paul@paul-moore.com>

kernel/audit.c

@@ -2365,7 +2365,7 @@ int audit_signal_info(int sig, struct task_struct *t)
  *
  * We can not do a netlink send inside an irq context because it blocks (last
  * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
- * queue and a tasklet is scheduled to remove them from the queue outside the
+ * queue and a kthread is scheduled to remove them from the queue outside the
  * irq context.  May be called in any context.
  */
 void audit_log_end(struct audit_buffer *ab)