[SCSI] libiscsi: fix session age rollover and remove cid encoding

The session age mask is only 4 bits, but session->age is 32. When
it gets larger then 15 and we try to or the bits some bits get
dropped and the check for session age in iscsi_verify_itt is useless.

The ISCSI_CID_MASK related bits are also useless since cid is always
one.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/include/scsi/iscsi_proto.h b/include/scsi/iscsi_proto.h
index 318a909..5ffec8a 100644
--- a/include/scsi/iscsi_proto.h
+++ b/include/scsi/iscsi_proto.h
@@ -45,8 +45,8 @@
 /* initiator tags; opaque for target */
 typedef uint32_t __bitwise__ itt_t;
 /* below makes sense only for initiator that created this tag */
-#define build_itt(itt, id, age) ((__force itt_t)\
-	((itt) | ((id) << ISCSI_CID_SHIFT) | ((age) << ISCSI_AGE_SHIFT)))
+#define build_itt(itt, age) ((__force itt_t)\
+	((itt) | ((age) << ISCSI_AGE_SHIFT)))
 #define get_itt(itt) ((__force uint32_t)(itt_t)(itt) & ISCSI_ITT_MASK)
 #define RESERVED_ITT ((__force itt_t)0xffffffff)