mmc: block: Fix is_waiting_last_req set incorrectly

Commit 15520111500c ("mmc: core: Further fix thread wake-up") allowed a
queue to release the host with is_waiting_last_req set to true. A queue
waiting to claim the host will not reset it, which can result in the
queue getting stuck in a loop.

Fixes: 15520111500c ("mmc: core: Further fix thread wake-up")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org # v4.10+
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/core/block.c

@@ -1817,6 +1817,7 @@ void mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
 		mmc_blk_issue_flush(mq, req);
 	} else {
 		mmc_blk_issue_rw_rq(mq, req);
+		card->host->context_info.is_waiting_last_req = false;
 	}
 
 out: