net: systemport: Manage Wake-on-LAN clock

It is necessary to manage the Wake-on-LAN clock to turn on the
appropriate blocks for MPD or CFP-based packet matching to work
otherwise we will not be able to reliably match packets during suspend.

Reported-by: Blair Prescott <blair.prescott@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>