pasemi_mac: Fix local-mac-address parsing

Turns out we have an old version of firmware that stores the mac address
in 'mac-address' as a string instead of a byte array. All versions that
use local-mac-address should have it as byte array, so no need to do
string parsing for that case.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>