futex: Drop leftover wake_q_add() comment

Since the original comment, we have moved to do the task
reference counting explicitly along with wake_q_add_safe().
Drop the now incorrect comment.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Link: https://lkml.kernel.org/r/20191023033450.6445-1-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/futex.c

@@ -1480,7 +1480,7 @@ static void mark_wake_futex(struct wake_q_head *wake_q, struct futex_q *q)
 
 	/*
 	 * Queue the task for later wakeup for after we've released
-	 * the hb->lock. wake_q_add() grabs reference to p.
+	 * the hb->lock.
 	 */
 	wake_q_add_safe(wake_q, p);
 }