net: qmi_wwan: add Option GTM681W

A standard Gobi 3000 reference design module.

Reported-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c
index 1d1021c..e4a0843 100644
--- a/drivers/net/usb/qmi_wwan.c
+++ b/drivers/net/usb/qmi_wwan.c
@@ -612,6 +612,7 @@
 	{QMI_GOBI_DEVICE(0x05c6, 0x9265)},	/* Asus Gobi 2000 Modem device (VR305) */
 	{QMI_GOBI_DEVICE(0x05c6, 0x9235)},	/* Top Global Gobi 2000 Modem device (VR306) */
 	{QMI_GOBI_DEVICE(0x05c6, 0x9275)},	/* iRex Technologies Gobi 2000 Modem device (VR307) */
+	{QMI_GOBI_DEVICE(0x0af0, 0x8120)},	/* Option GTM681W */
 	{QMI_GOBI_DEVICE(0x1199, 0x68a5)},	/* Sierra Wireless Modem */
 	{QMI_GOBI_DEVICE(0x1199, 0x68a9)},	/* Sierra Wireless Modem */
 	{QMI_GOBI_DEVICE(0x1199, 0x9001)},	/* Sierra Wireless Gobi 2000 Modem device (VT773) */