qcacmn: Add APIs to set and get acs_mode in vdev mlme obj

To support fixed channel SAP in unsafe channels, driver needs
to cache and retrieve SAP start mode i.e. ACS or fixed.
Add a new param is_acs_mode to vdev_mlme_mgmt_ap and APIs to
set and get the same through vdev.

Change-Id: Ib274b95be66e774b15f4687a02ed7fef6bf21056
CRs-Fixed: 3381401

umac/mlme/include/wlan_vdev_mlme.h

@@ -435,6 +435,7 @@ struct wlan_vdev_aid_mgr {
  * @max_chan_switch_time: Max channel switch time in milliseconds.
  * @last_bcn_ts_ms: Timestamp (in milliseconds) of the last beacon sent on the
  *                  CSA triggered channel.
+ * @is_acs_mode: True if SAP is started in ACS mode
  */
 struct vdev_mlme_mgmt_ap {
 	bool hidden_ssid;
@@ -442,6 +443,7 @@ struct vdev_mlme_mgmt_ap {
 	struct wlan_vdev_aid_mgr *aid_mgr;
 	uint32_t max_chan_switch_time;
 	unsigned long last_bcn_ts_ms;
+	bool is_acs_mode;
 };
 
 /**