scsi: core: Remove scsi_cmnd.tag

It is never read, so get rid of it.

Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: Hannes Reinecke <[e-mail]>
Reviewed-by: Bart Van Assche <[e-mail]>
Reviewed-by: Christoph Hellwig <[e-mail]>
Signed-off-by: John Garry <[e-mail]>
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/scsi/scsi_lib.c

···
 
 	scsi_init_command(sdev, cmd);
 
-	cmd->tag = req->tag;
 	cmd->prot_op = SCSI_PROT_NORMAL;
 	if (blk_rq_bytes(req))
 		cmd->sc_data_direction = rq_dma_dir(req);

include/scsi/scsi_cmnd.h

···
 	int flags;		/* Command flags */
 	unsigned long state;	/* Command completion state */
 
-	unsigned char tag;	/* SCSI-II queued command tag */
 	unsigned int extra_len;	/* length of alignment and padding */
 };