b43: Implement RC calibration for rev.0/1 LP-PHYs

Also implement get/set BB mult, get/set TX gain, set RX gain,
disable/restore CRS, run/stop DDFS, RX IQ est and QDIV roundup
in the process.

Signed-off-by: Gábor Stefanik <netrolller.3d@gmail.com>
Acked-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>