ieee802154: atusb: try to read permanent extended address from device

With version 0.3 the atusb firmware offers an interface to read a permanent
EUI64 address from the devices EEPROM. This patch checks if the firmware is
new enough and tries to read out and use the address. If this does not work
we fall back to the original randomly generated address.

Signed-off-by: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>