octeon_ep: delete unnecessary napi rollback under set_queues_err in octep_open()

octep_napi_add() and octep_napi_enable() are all after
netif_set_real_num_{tx,rx}_queues() in octep_open(), so it is unnecessary
napi rollback under set_queues_err. Delete them to fix it.

Fixes: 37d79d05 ("octeon_ep: add Tx/Rx processing and interrupt support")
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>