staging: comedi: acl7225b: cleanup acl7225b_di_insn_bits()

Use a local variable to hold the base register, 'reg', that is used
to read from the device.
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/acl7225b.c

@@ -64,8 +64,10 @@ static int acl7225b_di_insn_bits(struct comedi_device *dev,
 				 struct comedi_insn *insn,
 				 unsigned int *data)
 {
-	data[1] = inb(dev->iobase + (unsigned long)s->private) |
-	    (inb(dev->iobase + (unsigned long)s->private + 1) << 8);
+	unsigned long reg = (unsigned long)s->private;
+
+	data[1] = inb(dev->iobase + reg) |
+		  (inb(dev->iobase + reg + 1) << 8);
 
 	return insn->n;
 }