wifi: ath10k: Check return value of ath10k_get_arvif() in ath10k_wmi_event_tdls_peer()

Return value of a function ath10k_get_arvif() is dereferenced without
checking for null in ath10k_wmi_event_tdls_peer(), but it is usually checked
for this function.

Make ath10k_wmi_event_tdls_peer() do check retval of ath10k_get_arvif().

Found by Linux Verification Center (linuxtesting.org) with SVACE.
Signed-off-by: Peter Kosyh <pkosyh@yandex.ru>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20221003091217.322598-1-pkosyh@yandex.ru

drivers/net/wireless/ath/ath10k/wmi-tlv.c

@@ -584,7 +584,14 @@ static void ath10k_wmi_event_tdls_peer(struct ath10k *ar, struct sk_buff *skb)
 			ath10k_warn(ar, "did not find station from tdls peer event");
 			goto exit;
 		}
+
 		arvif = ath10k_get_arvif(ar, __le32_to_cpu(ev->vdev_id));
+		if (!arvif) {
+			ath10k_warn(ar, "no vif for vdev_id %d found",
+				    __le32_to_cpu(ev->vdev_id));
+			goto exit;
+		}
+
 		ieee80211_tdls_oper_request(
 					arvif->vif, station->addr,
 					NL80211_TDLS_TEARDOWN,