ath11k: Add vdev start flag to disable hardware encryption

Firmware blocks all data traffic until the key is plumbed. But, with
software encryption mode, key is never plumbed to firmware. Due to this,
a traffic failure in software encryption mode has been observed. Hence,
firmware has introduced a flag to differentiate software encryption
mode. This flag can be passed during vdev_start command.

Enable WMI_VDEV_START_HW_ENCRYPTION_DISABLED flag in vdev_start command
to notify firmware to disable hardware encryption for a vdev. This is set
if raw mode software encryption is enabled.

Tested-on: IPQ8074 hw2.0 AHB WLAN.HK.2.4.0.1-01421-QCAHKSWPL_SILICONZ-1

Signed-off-by: Seevalamuthu Mariappan <seevalam@codeaurora.org>
Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210721212029.142388-5-jouni@codeaurora.org