ath10k: fix memory leak for tpc_stats_final

The memory of ar->debug.tpc_stats_final is reallocated every debugfs
reading, it should be freed in ath10k_debug_destroy() for the last
allocation.

Tested HW: QCA9984
Tested FW: 10.4-3.9.0.2-00035
Signed-off-by: Miaoqing Pan <miaoqing@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/ath10k/debug.c

@@ -2532,6 +2532,7 @@ void ath10k_debug_destroy(struct ath10k *ar)
 	ath10k_debug_fw_stats_reset(ar);
 
 	kfree(ar->debug.tpc_stats);
+	kfree(ar->debug.tpc_stats_final);
 }
 
 int ath10k_debug_register(struct ath10k *ar)