ixgbe: Add receive length error counter

ixgbe enabled rlec counter and the rx_error used it.
We can export the counter directly via ethtool -S ethX.

Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>