staging: comedi: ni_daq_dio24: local symbols should not be exported

The symbol dio24_cs_driver is only referenced in this file. Make
it static.
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/ni_daq_dio24.c

@@ -308,7 +308,7 @@ MODULE_DESCRIPTION("Comedi driver for National Instruments "
 		   "PCMCIA DAQ-Card DIO-24");
 MODULE_LICENSE("GPL");
 
-struct pcmcia_driver dio24_cs_driver = {
+static struct pcmcia_driver dio24_cs_driver = {
 	.probe = dio24_cs_attach,
 	.remove = dio24_cs_detach,
 	.suspend = dio24_cs_suspend,