i40e: group autoneg PHY types together

This separates the setting of autoneg in i40e_phy_types_to_ethtool into
its own conditional.  Doing this adds clarity as what PHYs
support/advertise autoneg and makes it easier to add new PHY types in
the future.

This also fixes an issue on devices with CRT_RETIMER where advertising
autoneg was being set, but supported autoneg was not.

Signed-off-by: Alan Brady <alan.brady@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>