e1000e/igb/ixgbe: Don't report an error if devices don't support AER

The only error returned by pci_{en,dis}able_pcie_error_reporting() is
-EIO which simply means that Advanced Error Reporting is not supported.
There is no need to report that, so remove the error check from e1000e,
igb and ixgbe.

Signed-off-by: Frans Pop <elendil@planet.nl>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>