block: renumber REQ_OP_WRITE_ZEROES

Make life easy for implementations that needs to send a data buffer
to the device (e.g. SCSI) by numbering it as a data out command.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

include/linux/blk_types.h

@@ -174,7 +174,7 @@ enum req_opf {
 	/* write the same sector many times */
 	REQ_OP_WRITE_SAME	= 7,
 	/* write the zero filled sector many times */
-	REQ_OP_WRITE_ZEROES	= 8,
+	REQ_OP_WRITE_ZEROES	= 9,
 
 	/* SCSI passthrough using struct scsi_request */
 	REQ_OP_SCSI_IN		= 32,