qcacmn: Fix wlan_scan_manager.[ch] documentation

The kernel-doc script identified several documentation issues in
wlan_scan_manager.c and wlan_scan_manager.h, so fix them.

Change-Id: I372a336fdddc59256519b987aa2422ad077229e4
CRs-Fixed: 3335514

umac/scan/core/src/wlan_scan_manager.c

@@ -1038,6 +1038,7 @@ scm_update_channel_list(struct scan_start_request *req,
 /**
  * scm_req_update_dwell_time_as_per_scan_mode() - update scan req params
  * dwell time as per scan mode.
+ * @vdev: vdev to update
  * @req: scan request
  *
  * Return: void

umac/scan/core/src/wlan_scan_manager.h

@@ -31,7 +31,7 @@
 #include "wlan_scan_manager_6ghz.h"
 
 /**
- * struct scan_event_listners - listeners interested in a particular scan event
+ * struct scan_event_listeners - listeners interested in a particular scan event
  * @count: number of listeners
  * @cb: callback handler
  */
@@ -51,7 +51,6 @@ bool scm_is_scan_allowed(struct wlan_objmgr_vdev *vdev);
 /**
  * scm_scan_start_req() - scan start req core api
  * @msg: scheduler message object containing start scan req params
- * @req: start scan req params
  *
  * The API to start a scan
  *
@@ -62,7 +61,6 @@ QDF_STATUS scm_scan_start_req(struct scheduler_msg *msg);
 /**
  * scm_scan_cancel_req() - scan cancel req core api
  * @msg: scheduler message object containing stop scan params
- * @req: stop scan params
  *
  * The API to cancel a scan
  *