b43: fix reading info about radio for new devices (cores 40 & 42)

This changes
b43-phy0: Found Radio: Manuf 0x17F, Version 0x7769, Revision 4
to the
b43-phy0: Found Radio: Manuf 0x17F, Version 0x2069, Revision 4
which matches what closed source driver reports:
$ wl revinfo
radiorev 0x42069000

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