igc: Fix Energy Efficient Ethernet support declaration

The commit 01cf893b ("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: 01cf893b

 ("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>