staging: comedi: rti800: swap val and mask when reading ai data

The (mask & val) operation when reading the high 4-bits of the analog
data looks strange. Change it to (val & mask).
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/rti800.c

@@ -217,7 +217,7 @@ static int rti800_ai_insn_read(struct comedi_device *dev,
 			return ret;
 
 		data[i] = inb(dev->iobase + RTI800_ADCLO);
-		data[i] |= (0xf & inb(dev->iobase + RTI800_ADCHI)) << 8;
+		data[i] |= (inb(dev->iobase + RTI800_ADCHI) & 0xf) << 8;
 
 		if (devpriv->adc_2comp)
 			data[i] ^= 0x800;