USB: serial: qcserial: add Dell DW5570 QDL

The Dell DW5570 is a re-branded Sierra Wireless MC8805 which will by
default boot with vid 0x413c and pid 0x81a3. When triggered QDL download
mode, the device switches to pid 0x81a6 and provides the standard TTY
used for firmware upgrade.

Cc: <stable@vger.kernel.org>
Signed-off-by: Aleksander Morgado <aleksander@aleksander.es>
Signed-off-by: Johan Hovold <johan@kernel.org>

drivers/usb/serial/qcserial.c

@@ -124,6 +124,7 @@ static const struct usb_device_id id_table[] = {
 	{USB_DEVICE(0x1410, 0xa021)},	/* Novatel Gobi 3000 Composite */
 	{USB_DEVICE(0x413c, 0x8193)},	/* Dell Gobi 3000 QDL */
 	{USB_DEVICE(0x413c, 0x8194)},	/* Dell Gobi 3000 Composite */
+	{USB_DEVICE(0x413c, 0x81a6)},	/* Dell DW5570 QDL (MC8805) */
 	{USB_DEVICE(0x1199, 0x68a4)},	/* Sierra Wireless QDL */
 	{USB_DEVICE(0x1199, 0x68a5)},	/* Sierra Wireless Modem */
 	{USB_DEVICE(0x1199, 0x68a8)},	/* Sierra Wireless QDL */