USB: Add device id for Sierra Wireless MC8755

Adds the device id used by the UMTS cards in Lenovo X60s notebooks sold
in Europe.

Signed-off-by: Jan Luebbe <jluebbe@lasnet.de>
Cc: Kevin Lloyd <linux@sierrawireless.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/serial/sierra.c b/drivers/usb/serial/sierra.c
index 6bdb117..ea16572 100644
--- a/drivers/usb/serial/sierra.c
+++ b/drivers/usb/serial/sierra.c
@@ -37,6 +37,7 @@
 	{ USB_DEVICE(0x1199, 0x0019) },	/* Sierra Wireless AirCard 595 */
 	{ USB_DEVICE(0x1199, 0x6802) },	/* Sierra Wireless MC8755 */
 	{ USB_DEVICE(0x1199, 0x6803) },	/* Sierra Wireless MC8765 */
+	{ USB_DEVICE(0x1199, 0x6804) },	/* Sierra Wireless MC8755 for Europe */
 	{ USB_DEVICE(0x1199, 0x6812) },	/* Sierra Wireless MC8775 */
 	{ USB_DEVICE(0x1199, 0x6820) },	/* Sierra Wireless AirCard 875 */