rx_bits_phy is documented but not shown in ethtool --statistics.
Make this value available via ethtool.

According to existing documentation, rx_bits_phy is needed to calculate the
error rate from rx_pcs_symbol_err_phy and rx_corrected_bits_phy. The
existing rx_bytes_phy cannot be used for this calculation as it appears
to be a counter above the PHY in the strict sense (i.e. traffic based).

To avoid confusion, it might be better to use a different name (e.g.,
rx_bits_pcs), but for now, I will submit the patch as per the
documentation.

Signed-off-by: Kenta Akagi <k@mgml.me>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_stats.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c
index a2802cfc9b98..e167355daad5 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c
@@ -1226,6 +1226,7 @@ static const struct counter_desc pport_phy_layer_cntrs_stats_desc[] = {
 	MLX5_BYTE_OFF(ppcnt_reg, \
 		      counter_set.phys_layer_statistical_cntrs.c##_high)
 static const struct counter_desc pport_phy_statistical_stats_desc[] = {
+	{ "rx_bits_phy", PPORT_PHY_STATISTICAL_OFF(phy_received_bits) },
 	{ "rx_pcs_symbol_err_phy", PPORT_PHY_STATISTICAL_OFF(phy_symbol_errors) },
 	{ "rx_corrected_bits_phy", PPORT_PHY_STATISTICAL_OFF(phy_corrected_bits) },
 };
-- 
2.50.1