qcacld-3.0: Validate wdev before accessing netdev

Validate wdev before accessing netdev in __wlan_hdd_cfg80211_set_txpower.
Avoid invalid memory access.

Change-Id: I48af4e458ef7571cfdf9f157cdb8c3427fff4fc7
CRs-Fixed: 2487005

core/hdd/src/wlan_hdd_power.c

@@ -2020,7 +2020,7 @@ static int __wlan_hdd_cfg80211_set_txpower(struct wiphy *wiphy,
 {
 	struct hdd_context *hdd_ctx = (struct hdd_context *) wiphy_priv(wiphy);
 	mac_handle_t mac_handle;
-	struct hdd_adapter *adapter = WLAN_HDD_GET_PRIV_PTR(wdev->netdev);
+	struct hdd_adapter *adapter;
 	struct qdf_mac_addr bssid = QDF_MAC_ADDR_BCAST_INIT;
 	struct qdf_mac_addr selfmac;
 	QDF_STATUS status;
@@ -2029,6 +2029,13 @@ static int __wlan_hdd_cfg80211_set_txpower(struct wiphy *wiphy,
 
 	hdd_enter();
 
+	if (!wdev) {
+		hdd_err("wdev is null, set tx power failed");
+		return -EIO;
+	}
+
+	adapter = WLAN_HDD_GET_PRIV_PTR(wdev->netdev);
+
 	if (QDF_GLOBAL_FTM_MODE == hdd_get_conparam()) {
 		hdd_err("Command not allowed in FTM mode");
 		return -EINVAL;