qcacmn: Fix memory overflow in wmi roam scan filter cmd

The length of buffer used to send wmi roam scan filter cmd is not
properly calculated and thus the length is less than the actual data
to be copied.

Fix it by properly calculating the length of the buffer.

Change-Id: I6a3baa5ca5560d2d04f9bd41a709a37abc1b95a9
CRs-Fixed: 2072057

wmi_unified_param.h

@@ -3152,7 +3152,6 @@ struct ssid_hotlist_param {
 /**
  * struct roam_scan_filter_params - Structure holding roaming scan
  *                                  parameters
- * @len:                      length
  * @op_bitmap:                bitmap to determine reason of roaming
  * @session_id:               vdev id
  * @num_bssid_black_list:     The number of BSSID's that we should
@@ -3182,7 +3181,6 @@ struct ssid_hotlist_param {
  */
 
 struct roam_scan_filter_params {
-	uint32_t len;
 	uint32_t op_bitmap;
 	uint8_t session_id;
 	uint32_t num_bssid_black_list;