ARM: Kirkwood: Recognize A1 revision of 6282 chip

Recognize the Kirkwood 6282 revision A1 chip since products using
this chip are shipping now, such as the QNAP TS-x19P II devices.

Signed-off-by: Martin Michlmayr <tbm@cyrius.com>
Acked-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>