The block layer now handles zone write locking.

[mkp: removed SCMD_ZONE_WRITE_LOCK reference in scsi_debugfs]
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>