staging: comedi: amplc_pci230: fix a precedence bug

The addition operation has higher precedence than ?: so this would write
to PCI230_DACOUT1 instead of devpriv->daqio + PCI230_DACOUT1.

Fixes: 4f9c63fe ('staging: comedi: amplc_pci230: refactor iobase addresses')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>