sfc: Disable setting feature flags that are not implemented

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/sfc/ethtool.c

@@ -888,7 +888,6 @@ const struct ethtool_ops efx_ethtool_ops = {
 	/* Need to enable/disable TSO-IPv6 too */
 	.set_tso		= efx_ethtool_set_tso,
 	.get_flags		= ethtool_op_get_flags,
-	.set_flags		= ethtool_op_set_flags,
 	.get_sset_count		= efx_ethtool_get_sset_count,
 	.self_test		= efx_ethtool_self_test,
 	.get_strings		= efx_ethtool_get_strings,