scsi: Add CDB definition for COMPARE_AND_WRITE

Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>
diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h
index 4b87d99..6268062 100644
--- a/include/scsi/scsi.h
+++ b/include/scsi/scsi.h
@@ -144,6 +144,7 @@
 #define ACCESS_CONTROL_IN     0x86
 #define ACCESS_CONTROL_OUT    0x87
 #define READ_16               0x88
+#define COMPARE_AND_WRITE     0x89
 #define WRITE_16              0x8a
 #define READ_ATTRIBUTE        0x8c
 #define WRITE_ATTRIBUTE	      0x8d