net: bcmgenet: Request APD, DLL disable and IDDQ-SR

When interfacing with a Broadcom PHY, request the auto-power down, DLL
disable and IDDQ-SR modes to be enabled.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>