net: ethtool: remove unused struct 'cable_test_tdr_req_info'

'cable_test_tdr_req_info' is unused since the original
commit f2bc8ad3 ("net: ethtool: Allow PHY cable test TDR data to
configured").

Remove it.
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ethtool/cabletest.c

@@ -207,10 +207,6 @@ int ethnl_cable_test_fault_length(struct phy_device *phydev, u8 pair, u32 cm)
 }
 EXPORT_SYMBOL_GPL(ethnl_cable_test_fault_length);
 
-struct cable_test_tdr_req_info {
-	struct ethnl_req_info		base;
-};
-
 static const struct nla_policy cable_test_tdr_act_cfg_policy[] = {
 	[ETHTOOL_A_CABLE_TEST_TDR_CFG_FIRST]	= { .type = NLA_U32 },
 	[ETHTOOL_A_CABLE_TEST_TDR_CFG_LAST]	= { .type = NLA_U32 },