In preparation for implementing the power down GPHY sequence, rename
bcmgenet_ephy_power_up to illustrate that it is not EPHY specific but
PHY agnostic, and add an "enable" argument.
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>