cc2520: Set short address and ieee address from the driver

For hw filtering and autoack to work, all the information should be
properly set in the chip.

That's a fix for the legacy radio/net API. From original code, these
were set from the application which is bad. But setting it from the
driver is not any better. ieee802154 and net stack should know what to
do, that will be fixed in the future.

Change-Id: I1688223e9488d10a423e788eb88ba1e251cb3f88
Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>