net: irda: ks959: constify usb_device_id

usb_device_id are not supposed to change at runtime. All functions
working with usb_device_id provided by <linux/usb.h> work with
const usb_device_id. So mark the non-const structs as const.
Signed-off-by: NArvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/irda/ks959-sir.c

@@ -133,7 +133,7 @@
 #define KS959_PRODUCT_ID 0x4959
 
 /* These are the currently known USB ids */
-static struct usb_device_id dongles[] = {
+static const struct usb_device_id dongles[] = {
 	/* KingSun Co,Ltd  IrDA/USB Bridge */
 	{USB_DEVICE(KS959_VENDOR_ID, KS959_PRODUCT_ID)},
 	{}