net/ipv6: stop leaking percpu memory in fib6 info

The fib6_info_alloc() function allocates percpu memory to hold per CPU
pointers to rt6_info, but this memory is never freed. Fix it.

Fixes: a64efe14 ("net/ipv6: introduce fib6_info struct and helpers")
Signed-off-by: NMike Rapoport <rppt@linux.vnet.ibm.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/ip6_fib.c

@@ -196,6 +196,8 @@ void fib6_info_destroy_rcu(struct rcu_head *head)
 				*ppcpu_rt = NULL;
 			}
 		}
+
+		free_percpu(f6i->rt6i_pcpu);
 	}
 
 	lwtstate_put(f6i->fib6_nh.nh_lwtstate);