wcn36xx: Rename wcn36xx_vif.ucast_dpu_signature to self_ucast_dpu_sign

This is more line with the names of the other members

Signed-off-by: Pontus Fuchs <pontus.fuchs@gmail.com>
wcn36xx: Track dpu signature per sta

This fixes problems seen with multiple softap clients and reconnecting
softap clients.

Signed-off-by: Pontus Fuchs <pontus.fuchs@gmail.com>
wcn36xx: Update dtim period before starting BSS

The dtim period sent to FW was 0 because the dtim period
was never set. This caused an incorrect dtim count to be sent in
beacons.

Signed-off-by: Pontus Fuchs <pontus.fuchs@gmail.com>
Merge pull request #132 from pof2/softap_fixes

Softap fixes