s390/qeth: allocate RX queue at probe time

We always need an RX queue, and there's no reconfig situation either
where we would need to free & rebuild the queue.

So allocate the RX queue right from the start, and avoid freeing it
during unrelated qeth_free_qdio_queues() calls.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>