drivers: net: xgene: Add frame recovered statistics counter for errata 10GE_8/ENET_11

This patch adds statistic counter for frames recovered from HW errata
10GE_8 and ENET_11:
"HW reports Length error for valid 64 byte frames with len <46 bytes".

Signed-off-by: Quan Nguyen <qnguyen@apm.com>
Signed-off-by: Iyappan Subramanian <isubramanian@apm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>