r8152: load the default MAC address

Except for RTL_VER_01, replace loading the MAC address from PLA_IDR
with from PLA_BACKUP. The default MAC address may be modified by
the other OS, so the PLA_IDR may be not the default MAC address.

The data in the PLA_BACKUP address of the RTL_VER_01 may be destoryed,
so load MAC address from PLA_IDR for RTL_VER_01.

Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>