drivers: net: xgene: Add workaround for errata 10GE_8/ENET_11

This patch implements workaround for errata 10GE_8 and ENET_11:
"HW reports length error for valid 64 byte frames with len <46 bytes"
by recovering them from error.

Signed-off-by: Iyappan Subramanian <isubramanian@apm.com>
Signed-off-by: Quan Nguyen <qnguyen@apm.com>
Signed-off-by: Toan Le <toanle@apm.com>
Tested-by: Fushen Chen <fchen@apm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>