[IPV6] MIP6: Add Mobility header definition.

Add Mobility header definition for Mobile IPv6.
Based on MIPL2 kernel patch.

This patch was also written by: Antti Tuominen <anttit@tcs.hut.fi>

Signed-off-by: Masahide NAKAMURA <nakam@linux-ipv6.org>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/in6.h b/include/linux/in6.h
index 086ec2a..d776829 100644
--- a/include/linux/in6.h
+++ b/include/linux/in6.h
@@ -134,6 +134,7 @@
 #define IPPROTO_ICMPV6		58	/* ICMPv6			*/
 #define IPPROTO_NONE		59	/* IPv6 no next header		*/
 #define IPPROTO_DSTOPTS		60	/* IPv6 destination options	*/
+#define IPPROTO_MH		135	/* IPv6 mobility header		*/
 
 /*
  *	IPv6 TLV options.