net: bcmgenet: use MAC link status for fixed phy

When using the fixed PHY with GENET (e.g. MOCA) the PHY link
status can be determined from the internal link status captured
by the MAC. This allows the PHY state machine to use the correct
link state with the fixed PHY even if MAC link event interrupts
are missed when the net device is opened.

Fixes: 8d88c6eb ("net: bcmgenet: enable MoCA link state change detection")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>