r8152: Use MAC address from device tree if available

r8152: Use MAC address from device tree if available

If a MAC address was passed via the device tree node for the r8152
device, use it and fall back to reading from EEPROM otherwise. This is
useful for devices where the r8152 EEPROM was not programmed with a
valid MAC address, or if users want to explicitly set a MAC address in
the bootloader and pass that to the kernel.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>