rtw88: fix seq_file memory leak

When using single_open(), single_release() should be used instead
of seq_release(), otherwise there is a memory leak.

This is detected by Coccinelle semantic patch.

Fixes: e3037485 ("rtw88: new Realtek 802.11ac driver")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/realtek/rtw88/debug.c

@@ -77,7 +77,7 @@ static const struct file_operations file_ops_single_r = {
 	.open = rtw_debugfs_single_open_rw,
 	.read = seq_read,
 	.llseek = seq_lseek,
-	.release = seq_release,
+	.release = single_release,
 };
 
 static const struct file_operations file_ops_single_rw = {