net/macb: sqe_test_errors are TX errors, not RX errors

The statistics are grouped by TX and RX errors.
The SQE Test Errors Register indicates problems with TX.

Signed-off-by: Wolfgang Steinwender <wsteinwender@pcs.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>