ath6kl: Use delayed key configuration for WAPI in AP mode

This is needed to allow WAPI AP to configure the initial group key
to the target in the same way as is done with TKIP/CCMP. This
fixes broadcast data frame delivery with the initial group key.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>