ipv6: rt6_info output redirect to tunnel output

This is similar to ipv4 redirect of dst output to lwtunnel
output function for encapsulation and xmit.

Signed-off-by: Roopa Prabhu <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/ipv6/route.c

···
 			goto out;
 		lwtunnel_state_get(lwtstate);
 		rt->rt6i_lwtstate = lwtstate;
+		rt->dst.output = lwtunnel_output6;
 	}
 
 	ipv6_addr_prefix(&rt->rt6i_dst.addr, &cfg->fc_dst, cfg->fc_dst_len);