The phy is connected at early stage of probe but not properly
disconnected if error occurs.  This patch fixes the issue.

Also changing the return type of xgene_enet_check_phy_handle(),
since this function always returns success.
Signed-off-by: Quan Nguyen <qnguyen@apm.com>
Signed-off-by: Iyappan Subramanian <isubramanian@apm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>