wifi: ath12k: fix dfs-radar and temperature event locking

The ath12k active pdevs are protected by RCU but the DFS-radar and
temperature event handling code calling ath12k_mac_get_ar_by_pdev_id()
was not marked as a read-side critical section.

Mark the code in question as RCU read-side critical sections to avoid
any potential use-after-free issues.

Note that the temperature event handler looks like a place holder
currently but would still trigger an RCU lockdep splat.

Compile tested only.

Fixes: d8899132 ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
Cc: stable@vger.kernel.org	# v6.2
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20231019113650.9060-2-johan+linaro@kernel.org

drivers/net/wireless/ath/ath12k/wmi.c

@@ -6515,6 +6515,8 @@ ath12k_wmi_pdev_dfs_radar_detected_event(struct ath12k_base *ab, struct sk_buff
 		   ev->detector_id, ev->segment_id, ev->timestamp, ev->is_chirp,
 		   ev->freq_offset, ev->sidx);
 
+	rcu_read_lock();
+
 	ar = ath12k_mac_get_ar_by_pdev_id(ab, le32_to_cpu(ev->pdev_id));
 
 	if (!ar) {
@@ -6532,6 +6534,8 @@ ath12k_wmi_pdev_dfs_radar_detected_event(struct ath12k_base *ab, struct sk_buff
 		ieee80211_radar_detected(ar->hw);
 
 exit:
+	rcu_read_unlock();
+
 	kfree(tb);
 }
 
@@ -6550,11 +6554,16 @@ ath12k_wmi_pdev_temperature_event(struct ath12k_base *ab,
 	ath12k_dbg(ab, ATH12K_DBG_WMI,
 		   "pdev temperature ev temp %d pdev_id %d\n", ev.temp, ev.pdev_id);
 
+	rcu_read_lock();
+
 	ar = ath12k_mac_get_ar_by_pdev_id(ab, le32_to_cpu(ev.pdev_id));
 	if (!ar) {
 		ath12k_warn(ab, "invalid pdev id in pdev temperature ev %d", ev.pdev_id);
-		return;
+		goto exit;
 	}
+
+exit:
+	rcu_read_unlock();
 }
 
 static void ath12k_fils_discovery_event(struct ath12k_base *ab,