Common init used to be called by the driver when the first port comes up, mainly to reset and reload external PHY microcode.
However, in case management driver is active on the other port, traffic would halted. So limit the common init to be done only once after POR.

Signed-off-by: Yaniv Rosner <yanivr@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>