One thing this change pointed out was that we really should
pull the "get 'local-mac-address' property" logic into a helper
function all the network drivers can call.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This encodes a common idiomatic coding pattern used when
dealing with integer properties.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The basic framework is based on the PowerPC OF code.

This code even tries to get the device addressing components
correct in the full path names.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>