libertas: Add missing sentinel at end of if_usb.c fw_table

BugLink: https://bugs.launchpad.net/bugs/1848589

[ Upstream commit 764f3f1e ]

This sentinel tells the firmware loading process when to stop.

Reported-and-tested-by: syzbot+98156c174c5a2cad9f8f@syzkaller.appspotmail.com
Signed-off-by: Kevin Easton <kevin@guarana.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/net/wireless/libertas/if_usb.c

@@ -49,7 +49,8 @@ static const struct lbs_fw_table fw_table[] = {
 	{ MODEL_8388, "libertas/usb8388_v5.bin", NULL },
 	{ MODEL_8388, "libertas/usb8388.bin", NULL },
 	{ MODEL_8388, "usb8388.bin", NULL },
-	{ MODEL_8682, "libertas/usb8682.bin", NULL }
+	{ MODEL_8682, "libertas/usb8682.bin", NULL },
+	{ 0, NULL, NULL }
 };
 
 static struct usb_device_id if_usb_table[] = {