blk-mq: don't handle failure in .get_budget

It is enough to just check if we can get the budget via .get_budget().
And we don't need to deal with device state change in .get_budget().

For SCSI, one issue to be fixed is that we have to call
scsi_mq_uninit_cmd() to free allocated ressources if SCSI device fails
to handle the request. And it isn't enough to simply call
blk_mq_end_request() to do that if this request is marked as
RQF_DONTPREP.

Fixes: 0df21c86bdbf(scsi: implement .get_budget and .put_budget for blk-mq)
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 522b420..f97acef 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -147,14 +147,13 @@ static inline void blk_mq_put_dispatch_budget(struct blk_mq_hw_ctx *hctx)
 		q->mq_ops->put_budget(hctx);
 }
 
-static inline blk_status_t blk_mq_get_dispatch_budget(
-		struct blk_mq_hw_ctx *hctx)
+static inline bool blk_mq_get_dispatch_budget(struct blk_mq_hw_ctx *hctx)
 {
 	struct request_queue *q = hctx->queue;
 
 	if (q->mq_ops->get_budget)
 		return q->mq_ops->get_budget(hctx);
-	return BLK_STS_OK;
+	return true;
 }
 
 #endif