e100: Support RXALL feature flag.

This allows the NIC to receive packets with bad FCS
and other errors.  Good for sniffing packets on flakey
networks.

v4:  Only flax rx-over-length errors if pkt is beyond
   maximum expected packet size, not just beyond the MTU.
   This matches the existing logic for this counter.

Signed-off-by: Ben Greear <greearb@candelatech.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>