amd-xgbe: Add ECC status support for the device memory

Some versions of the amd-xgbe device are capable of reporting ECC error
information back to the driver. Add support to process, track and report
on this information.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>