blk-zoned: Remove the definition of blk_zone_start()

Commit e76239a3 ("block: add a report_zones method") removed the last
blk_zone_start() call. Hence also remove the definition of this function.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210406200820.15180-1-bvanassche@acm.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-zoned.c

@@ -52,14 +52,6 @@ const char *blk_zone_cond_str(enum blk_zone_cond zone_cond)
 }
 EXPORT_SYMBOL_GPL(blk_zone_cond_str);
 
-static inline sector_t blk_zone_start(struct request_queue *q,
-				      sector_t sector)
-{
-	sector_t zone_mask = blk_queue_zone_sectors(q) - 1;
-
-	return sector & ~zone_mask;
-}
-
 /*
  * Return true if a request is a write requests that needs zone write locking.
  */