atusb: add handling for different chipnames

This patch supports handling for printout different chipnames between
atusb and rzusb. The rzusb contains an at86rf230 and atusb an at86rf231
transceiver.

Cc: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>