net: seg6.h: remove an unused #include

A minor code cleanup.
Signed-off-by: Peter Oskolkov <posk@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/seg6.h

@@ -16,7 +16,6 @@
 
 #include <linux/net.h>
 #include <linux/ipv6.h>
-#include <net/lwtunnel.h>
 #include <linux/seg6.h>
 #include <linux/rhashtable-types.h>