net: dsa: qca8k: fix EEE init

net: dsa: qca8k: fix EEE init

The qca8k obviously copied code from the sf2 driver as how to set EEE:

    if (e->eee_enabled) {
        p->eee_enabled = qca8k_eee_init(ds, port, phydev);
        if (!p->eee_enabled)
            ret = -EOPNOTSUPP;
    }

But it did not use the same logic for the EEE init routine, which is
"Returns 0 if EEE was not enabled, or 1 otherwise". This results in
returning -EOPNOTSUPP on success and caching EEE enabled on failure.

This patch fixes the returned value of qca8k_eee_init.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>