igc: Fix Energy Efficient Ethernet support declaration

The commit 01cf893 ("net: intel: i40e/igc: Remove setting Autoneg in
EEE capabilities") removed SUPPORTED_Autoneg field but left inappropriate
ethtool_keee structure initialization. When "ethtool --show <device>"
(get_eee) invoke, the 'ethtool_keee' structure was accidentally overridden.
Remove the 'ethtool_keee' overriding and add EEE declaration as per IEEE
specification that allows reporting Energy Efficient Ethernet capabilities.

Examples:
Before fix:
ethtool --show-eee enp174s0
EEE settings for enp174s0:
	EEE status: not supported

After fix:
EEE settings for enp174s0:
	EEE status: disabled
	Tx LPI: disabled
	Supported EEE link modes:  100baseT/Full
	                           1000baseT/Full
	                           2500baseT/Full

Fixes: 01cf893 ("net: intel: i40e/igc: Remove setting Autoneg in EEE capabilities")
Suggested-by: Dima Ruinskiy <dima.ruinskiy@intel.com>
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Naama Meir <naamax.meir@linux.intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://lore.kernel.org/r/20240603-net-2024-05-30-intel-net-fixes-v2-6-e3563aa89b0c@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/intel/igc/igc_ethtool.c

@@ -1629,12 +1629,17 @@ static int igc_ethtool_get_eee(struct net_device *netdev,
 	struct igc_hw *hw = &adapter->hw;
 	u32 eeer;
 
+	linkmode_set_bit(ETHTOOL_LINK_MODE_2500baseT_Full_BIT,
+			 edata->supported);
+	linkmode_set_bit(ETHTOOL_LINK_MODE_1000baseT_Full_BIT,
+			 edata->supported);
+	linkmode_set_bit(ETHTOOL_LINK_MODE_100baseT_Full_BIT,
+			 edata->supported);
+
 	if (hw->dev_spec._base.eee_enable)
 		mii_eee_cap1_mod_linkmode_t(edata->advertised,
 					    adapter->eee_advert);
 
-	*edata = adapter->eee;
-
 	eeer = rd32(IGC_EEER);
 
 	/* EEE status on negotiated link */

drivers/net/ethernet/intel/igc/igc_main.c

@@ -12,6 +12,7 @@
 #include <linux/bpf_trace.h>
 #include <net/xdp_sock_drv.h>
 #include <linux/pci.h>
+#include <linux/mdio.h>
 
 #include <net/ipv6.h>
 
@@ -4975,6 +4976,9 @@ void igc_up(struct igc_adapter *adapter)
 	/* start the watchdog. */
 	hw->mac.get_link_status = true;
 	schedule_work(&adapter->watchdog_task);
+
+	adapter->eee_advert = MDIO_EEE_100TX | MDIO_EEE_1000T |
+			      MDIO_EEE_2_5GT;
 }
 
 /**