ixgbe: Fix link capabilities during adapter resets

Adapter link advertisement capabilities were not persistent during
adapter resets. While configuring multispeed fiber link check for
phy autoneg_advertised settings before overwriting with default
link capabilities

Signed-off-by: Mallikarjuna R Chilakala <mallikarjuna.chilakala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>