b43: Fix Bluetooth Coexistence SPROM programming error for HP 12f8 version of BCM4306

Yet another BCM4306 card with the Bluetooth Coexistence SPROM programming
error has been found.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>