net: ixgbe: reject unsupported coalescing params

Set ethtool_ops->supported_coalesce_params to let
the core reject unsupported coalescing parameters.

This driver did not previously reject unsupported parameters.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c

@@ -3444,6 +3444,7 @@ static int ixgbe_set_priv_flags(struct net_device *netdev, u32 priv_flags)
 }
 
 static const struct ethtool_ops ixgbe_ethtool_ops = {
+	.supported_coalesce_params = ETHTOOL_COALESCE_USECS,
 	.get_drvinfo            = ixgbe_get_drvinfo,
 	.get_regs_len           = ixgbe_get_regs_len,
 	.get_regs               = ixgbe_get_regs,