wl12xx: Add AP related definitions to HOST-FW interface

Change structures in a non-destructive manner. This means no
changes in size or location of existing members used by STA.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Reviewed-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>