USB: usbtmc: add device quirk for Rigol DS6104

Recently we purchased the Rigol DS6104 and when I try to operate it from
my Linux pc, everything works well with the default usbtmc driver,
except when I want to download a big datachunk like a screenshot. This
bitmapfile has a size of 1152054 bytes but I receive a smaller file and
no new packets can be read.

When I took a look at the driver source, I found this "Rigol quirk" and
I added the id of the new DS series oscilloscopes to this list. I
compiled it and loaded the new driver and now everything seems to work
fine.
Signed-off-by: Teunis van Beelen <teuniz@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/class/usbtmc.c

@@ -109,6 +109,7 @@ struct usbtmc_ID_rigol_quirk {
 
 static const struct usbtmc_ID_rigol_quirk usbtmc_id_quirk[] = {
 	{ 0x1ab1, 0x0588 },
+	{ 0x1ab1, 0x04b0 },
 	{ 0, 0 }
 };