staging: comedi: das08: Correct AO output for das08jr-16-ao

Don't zero out bits 15..12 of the data value in `das08jr_ao_winsn()` as
that knobbles the upper three-quarters of the output range for the
'das08jr-16-ao' board.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: NIan Abbott <abbotti@mev.co.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/das08.c

@@ -378,7 +378,7 @@ das08jr_ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,
 	int chan;
 
 	lsb = data[0] & 0xff;
-	msb = (data[0] >> 8) & 0xf;
+	msb = (data[0] >> 8) & 0xff;
 
 	chan = CR_CHAN(insn->chanspec);