net: mv643xx_eth: 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/marvell/mv643xx_eth.c

@@ -1737,6 +1737,7 @@ static int mv643xx_eth_get_sset_count(struct net_device *dev, int sset)
 }
 
 static const struct ethtool_ops mv643xx_eth_ethtool_ops = {
+	.supported_coalesce_params = ETHTOOL_COALESCE_USECS,
 	.get_drvinfo		= mv643xx_eth_get_drvinfo,
 	.nway_reset		= phy_ethtool_nway_reset,
 	.get_link		= ethtool_op_get_link,