net: Clean Up PHY Handling in Axxia FEMAC

commit 0bed36803863445b4d25bed39b353ef62b197ad2 from
https://github.com/axxia/linux-yocto.git v5.10/standard/axxia-dev/base.

Connecting to the PHY needs to happen in *probe(), not in
*open().  Otherwise ifconfig down/ifconfig up fails.

Signed-off-by: John Jacques <john.jacques@intel.com>
Signed-off-by: Liwei Song <liwei.song@windriver.com>