Revert "blk-rq-qos: remove redundant finish_wait to rq_qos_wait."

This reverts commit 826f2f48.

Qian Cai reports that this commit causes stalls with swap. Revert until
the reason can be figured out.
Reported-by: NQian Cai <cai@lca.pw>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

block/blk-rq-qos.c

@@ -273,6 +273,8 @@ void rq_qos_wait(struct rq_wait *rqw, void *private_data,
 		if (data.got_token)
 			break;
 		if (!has_sleeper && acquire_inflight_cb(rqw, private_data)) {
+			finish_wait(&rqw->wait, &data.wq);
+
 			/*
 			 * We raced with wbt_wake_function() getting a token,
 			 * which means we now have two. Put our local token