wl12xx: use dynamic hlids for AP-mode

Using hlid=0 in AP mode is a bug. Dynamically allocate HLIDs.

Set the "first sta hlid" as 3. This will have to be changed
when multiple vifs will be supported.

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