Fix pstat behaviour when using coredumps. The reference to tp was

incorrect and should have been poining to &tty, tp is a virtual
address from the coredump, while we should obtain the address through
the tty struct.

Approved by:	imp (mentor, implicit trivial changes)
MFC after:	1 week
Submitted by:	Ed Schouten (ed at 80836 dot nl)

usr.sbin/pstat/pstat.c

@@ -246,7 +246,7 @@ ttymode_kvm(void)
 		XT_COPY(olowat);
 #undef XT_COPY
 		ttyprt(&xt);
-		tp = TAILQ_NEXT(tp, t_list);
+		tp = TAILQ_NEXT(&tty, t_list);
 	}
 }