llvm: Remove no-op subst on SunOS.

lang/llvm/Makefile

@@ -1,4 +1,4 @@
-# $NetBSD: Makefile,v 1.91 2023/10/06 19:15:20 adam Exp $
+# $NetBSD: Makefile,v 1.92 2023/10/09 11:31:08 jperkin Exp $
 #
 # When updating this, please also update:
 # devel/include-what-you-use
@@ -79,7 +79,6 @@ TEST_ENV+=		LD_LIBRARY_PATH=${WRKDIR}/build/lib
 # all platforms.  Change this to a patch if verified.
 SUBST_CLASSES.SunOS+=	linkmap
 SUBST_STAGE.linkmap=	pre-configure
-SUBST_FILES.linkmap=	tools/lto/lto.exports
 SUBST_FILES.linkmap+=	tools/remarks-shlib/Remarks.exports
 SUBST_SED.linkmap=	-e '/^LLVM/d'