USB: ftdi_sio: new device id for papouch AD4USB

added new device pid (PAPOUCH_AD4USB_PID) to ftdi_sio.h and ftdi_sio.c

AD4USB measuring converter is a 4-input A/D converter which enables the
user to measure to four current inputs ranging from 0(4) to 20 mA or
voltage between 0 and 10 V. The measured values are then transferred to
a superior system in digital form. The AD4USB communicates via USB.
Powered is also via USB.  datasheet in english is here:
http://www.papouch.com/shop/scripts/pdf/ad4usb_en.pdf


Signed-off-by: Radek Liboska <liboska@uochb.cas.cz>

diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 216f187..f6d8566 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -697,6 +697,7 @@
 	{ USB_DEVICE(RATOC_VENDOR_ID, RATOC_PRODUCT_ID_USB60F) },
 	{ USB_DEVICE(FTDI_VID, FTDI_REU_TINY_PID) },
 	{ USB_DEVICE(PAPOUCH_VID, PAPOUCH_QUIDO4x4_PID) },
+	{ USB_DEVICE(PAPOUCH_VID, PAPOUCH_AD4USB_PID) },
 	{ USB_DEVICE(FTDI_VID, FTDI_DOMINTELL_DGQG_PID) },
 	{ USB_DEVICE(FTDI_VID, FTDI_DOMINTELL_DUSB_PID) },
 	{ USB_DEVICE(ALTI2_VID, ALTI2_N3_PID) },