usb: typec: tcpm: free log buf memory when remove debug file

commit fd5da3e2 upstream.

The logbuffer memory should be freed when remove debug file.

Cc: stable@vger.kernel.org # v4.15+
Fixes: 4b4e02c8 ("typec: tcpm: Move out of staging")
Signed-off-by: Li Jun <jun.li@nxp.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20190717080646.30421-1-jun.li@nxp.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/tcpm.c

@@ -585,6 +585,15 @@ static void tcpm_debugfs_init(struct tcpm_port *port)
 
 static void tcpm_debugfs_exit(struct tcpm_port *port)
 {
+	int i;
+
+	mutex_lock(&port->logbuffer_lock);
+	for (i = 0; i < LOG_BUFFER_ENTRIES; i++) {
+		kfree(port->logbuffer[i]);
+		port->logbuffer[i] = NULL;
+	}
+	mutex_unlock(&port->logbuffer_lock);
+
 	debugfs_remove(port->dentry);
 }