[IPV6]: remove useless test in ip6_append_data

We've already dereferenced 'np' a dozen
times at this point, so it's safe to say it's not null.
Signed-off-by: NDave Jones <davej@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/ip6_output.c

@@ -890,7 +890,7 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
 		np->cork.hop_limit = hlimit;
 		np->cork.tclass = tclass;
 		mtu = dst_mtu(rt->u.dst.path);
-		if (np && np->frag_size < mtu) {
+		if (np->frag_size < mtu) {
 			if (np->frag_size)
 				mtu = np->frag_size;
 		}