[SCSI] libfc: add definition for task attribute mask

The FCP command header definition should define a mask for
the task attribute field.  This adds that #define.
Signed-off-by: NJoe Eykholt <jeykholt@cisco.com>
Signed-off-by: NRobert Love <robert.w.love@intel.com>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

include/scsi/fc/fc_fcp.h

@@ -76,6 +76,7 @@ struct fcp_cmnd32 {
 #define	FCP_PTA_HEADQ	    1	/* head of queue task attribute */
 #define	FCP_PTA_ORDERED     2	/* ordered task attribute */
 #define	FCP_PTA_ACA	    4	/* auto. contigent allegiance */
+#define	FCP_PTA_MASK	    7	/* mask for task attribute field */
 #define	FCP_PRI_SHIFT	    3	/* priority field starts in bit 3 */
 #define	FCP_PRI_RESVD_MASK  0x80	/* reserved bits in priority field */