staging: octeon-ethernet: remove .get_sg, etc. ethtool_ops

Driver sets .get_sg and .get_tx_csum ethtool_ops to their default
values anyway. Those fields are deprecated, starting in 2.6.39.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>