Split HW init sequence into AP/STA specific parts

The AP specific init sequence includes configuration of templates, rate
classes, power mode, etc. Also unmask AP specific events in the event mbox.

Separate the differences between AP and STA init into mode
specific functions called from wl1271_hw_init. The first is called after
radio configuration and the second after memory configuration.
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Reviewed-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>