ixgbe: Update setup PHY link to unset all speeds

This patch updates ixgbe_setup_phy_link_generic to set/unset
auto-negotiation for all speeds. This ensures that unsupported
speeds are unset. This is necessary since the PHY NVM may
advertise unsupported speeds.

Signed-off-by: Don Skidmore <donald.c.skidmore@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>