backports: handle new rxfh_ndir pointers in struct ethtool_ops

backports: handle new rxfh_ndir pointers in struct ethtool_ops

In kernel 3.3 struct ethtool_ops received 3 new function pointers
get_rxfh_indir_size, get_rxfh_indir, set_rxfh_indir.
Address this by putting ifdef around the code.

commit 7850f63f1620512631445b901ae11cd149e7375c
Author: Ben Hutchings <bhutchings@solarflare.com>
Date:   Thu Dec 15 13:55:01 2011 +0000

    ethtool: Centralise validation of ETHTOOL_{G, S}RXFHINDIR parameters

git describe --contains 7850f63f1620512631445b901ae11cd149e7375c
v3.3-rc1~182^2~192

Signed-off-by: Stefan Assmann <sassmann@kpanic.de>
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>