nl80211: Use the monitor interface only without device_ap_sme support

nl80211: Use the monitor interface only without device_ap_sme support

The places using drv->use_monitor were already skipping creation of the
monitor interface if drv->device_ap_sme == 0. This means that the
monitor interface operations would not have worked anyway and it is safe
to set drv->use_monitor to zero for all such cases. This fixes an issue
with management frame subscription not happening properly for the case
where the AP SME is in the driver and the driver supports monitor
interfaces (for other purposes).

This commit also removes the check for monitor support and the
previously used workaround that cleared drv->use_monitor in
drv->device_ap_sme == 1 case if monitor interface was not supported
since that condition cannot occur anymore.

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