i40e: Add EEE status getting & setting implementation

Implement Energy Efficient Ethernet (EEE) status getting & setting.
The i40e_get_eee() requesting PHY EEE capabilities from firmware.
The i40e_set_eee() function requests PHY EEE capabilities
from firmware and sets PHY EEE advertising to full abilities or 0
depending whether EEE is to be enabled or disabled.

Signed-off-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Tested-by: Tony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>