<net/route.h> should include IPv6 too.

Change-Id: I866097d8468aa8f326117d072444ebbc2a690719
diff --git a/libc/include/net/route.h b/libc/include/net/route.h
index a60df24..d26bfc9 100644
--- a/libc/include/net/route.h
+++ b/libc/include/net/route.h
@@ -1 +1,2 @@
 #include <linux/route.h>
+#include <linux/ipv6_route.h>