net: bcmgenet: correctly resume adapter from Wake-on-LAN

In case we configured the adapter to be a wake up source from
Wake-on-LAN, but we never actually woke up using Wake-on-LAN, we will
leave the adapter in MagicPacket matching mode, which prevents any other
type of packets from reaching the RX engine. Fix this by calling
bcmgenet_power_up() with GENET_POWER_WOL_MAGIC to restore the adapter
configuration in bcmgenet_resume().

The second problem we had was an imbalanced clock disabling in
bcmgenet_wol_resume(), the Wake-on-LAN slow clock is only enabled in
bcmgenet_suspend() if we configured Wake-on-LAN, yet we unconditionally
disabled the clock in bcmgenet_wol_resume().

Fixes: 8c90db72 ("net: bcmgenet: suspend and resume from Wake-on-LAN")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>