blk-mq-tag: kill unused tag enums

We don't have any notion of a tagging cache anymore, and haven't
for a long time. Kill off the unused enums.
Signed-off-by: NJens Axboe <axboe@kernel.dk>

block/blk-mq-tag.h

@@ -43,14 +43,9 @@ static inline struct sbq_wait_state *bt_wait_ptr(struct sbitmap_queue *bt,
 	return sbq_wait_ptr(bt, &hctx->wait_index);
 }
 
-enum {
-	BLK_MQ_TAG_CACHE_MIN	= 1,
-	BLK_MQ_TAG_CACHE_MAX	= 64,
-};
-
 enum {
 	BLK_MQ_TAG_FAIL		= -1U,
-	BLK_MQ_TAG_MIN		= BLK_MQ_TAG_CACHE_MIN,
+	BLK_MQ_TAG_MIN		= 1,
 	BLK_MQ_TAG_MAX		= BLK_MQ_TAG_FAIL - 1,
 };