b43: enable radio 0x2057 rev 9 (AKA BCM43228) support

Support for N-PHY rev 8 with 0x2057 rev 5 is almost ready, but we still
need to figure out how to handle rev 9 first.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>