Update to v4.15 kernel headers.

Test: NA.
Change-Id: Ic06b0506705a46ed11e3b9f212515d34147c8135
diff --git a/original/uapi/linux/in6.h b/original/uapi/linux/in6.h
index 2c002ff..ed291e5 100644
--- a/original/uapi/linux/in6.h
+++ b/original/uapi/linux/in6.h
@@ -285,6 +285,7 @@
 #define IPV6_TRANSPARENT        75
 #define IPV6_UNICAST_IF         76
 #define IPV6_RECVFRAGSIZE	77
+#define IPV6_FREEBIND		78
 
 /*
  * Multicast Routing: