[IPV6] __inet6_csk_dst_store(): fix check-after-use

The Coverity checker spotted that we have already oops'ed if "dst" was
NULL.

Since "dst" being NULL doesn't seem to be possible at this point this
patch removes the NULL check.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Masahide NAKAMURA <nakam@linux-ipv6.org>
Acked-by: Noriaki TAKAMIYA <takamiya@po.ntts.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/inet6_connection_sock.c

@@ -146,7 +146,7 @@ void __inet6_csk_dst_store(struct sock *sk, struct dst_entry *dst,
 	__ip6_dst_store(sk, dst, daddr, saddr);
 
 #ifdef CONFIG_XFRM
-	if (dst) {
+	{
 		struct rt6_info *rt = (struct rt6_info  *)dst;
 		rt->rt6i_flow_cache_genid = atomic_read(&flow_cache_genid);
 	}