qcacmn: Fix double free in wlan_cfg80211_scan()

In wlan_cfg80211_scan(), when "DNBS check fails", mem free of scan req is
done. Mem free of scan req is done again at the label "err" which would
end up in a double free.

Change-Id: Ib757832c1bd54372fba45cbc5ee306d0d7b233b0
CRs-Fixed: 2408703
diff --git a/os_if/linux/scan/src/wlan_cfg80211_scan.c b/os_if/linux/scan/src/wlan_cfg80211_scan.c
index 7bc4830..f74554d 100644
--- a/os_if/linux/scan/src/wlan_cfg80211_scan.c
+++ b/os_if/linux/scan/src/wlan_cfg80211_scan.c
@@ -1453,7 +1453,6 @@
 
 				if (QDF_IS_STATUS_ERROR(qdf_status)) {
 					cfg80211_err("DNBS check failed");
-					qdf_mem_free(req);
 					qdf_mem_free(chl);
 					chl = NULL;
 					ret = -EINVAL;