wl1271: add most of the normal initialization commands to PLT mode

We need to configure PLT mode almost in the same way as normal mode.  Most of
the configuration functions need to be called also when entering PLT, with
the exception of a few RX and TX configuration (which cause mac80211 warnings
if enable while runnning PLT tests).

Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Reviewed-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>