net: Use IS_ERR_OR_NULL().

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/flow.c

@@ -286,7 +286,7 @@ flow_cache_lookup(struct net *net, const struct flowi *key, u16 family, u8 dir,
 		else
 			fle->genid--;
 	} else {
-		if (flo && !IS_ERR(flo))
+		if (!IS_ERR_OR_NULL(flo))
 			flo->ops->delete(flo);
 	}
 ret_object: