USB: ftdi driver - add support for optical probe device

Added support for the Elster Unicom III Optical Probe.
The device ID has already been added to the usb.ids file.

Cc: stable <stable@kernel.org>
Signed-off-by: NEd Beroset <beroset@mindspring.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/usb/serial/ftdi_sio.c

@@ -568,6 +568,7 @@ static struct usb_device_id id_table_combined [] = {
 	{ USB_DEVICE(TELLDUS_VID, TELLDUS_TELLSTICK_PID) },
 	{ USB_DEVICE(FTDI_VID, FTDI_MAXSTREAM_PID) },
 	{ USB_DEVICE(TML_VID, TML_USB_SERIAL_PID) },
+	{ USB_DEVICE(FTDI_VID, FTDI_ELSTER_UNICOM_PID) },
 	{ USB_DEVICE(OLIMEX_VID, OLIMEX_ARM_USB_OCD_PID),
 		.driver_info = (kernel_ulong_t)&ftdi_olimex_quirk },
 	{ },					/* Optional parameter entry */

drivers/usb/serial/ftdi_sio.h

@@ -536,6 +536,8 @@
 #define OLIMEX_VID			0x15BA
 #define OLIMEX_ARM_USB_OCD_PID		0x0003
 
+/* www.elsterelectricity.com Elster Unicom III Optical Probe */
+#define FTDI_ELSTER_UNICOM_PID		0xE700 /* Product Id */
 
 /*
  * The Mobility Lab (TML)