Unifdef MAC label pointer in syncache entries -- in general, ifdef'd

structure contents are a bad idea in the kernel for binary
compatibility reasons, and this is a single pointer that is now included
in compiles by default anyway due to options MAC being in GENERIC.

sys/netinet/tcp_syncache.h

@@ -74,9 +74,7 @@ struct syncache {
 	struct toe_usrreqs *sc_tu;		/* TOE operations */
 	void 		*sc_toepcb;		/* TOE protocol block */
 #endif			
-#ifdef MAC
 	struct label	*sc_label;		/* MAC label reference */
-#endif
 	struct ucred	*sc_cred;		/* cred cache for jail checks */
 };