staging: comedi: do not return -ENOSYS.

fixed coding style issue by replacing ENOSYS
with EIO because it means 'invalid syscall nr'
and nothing else.

Signed-off-by: Ted Chen <[e-mail]>
Reviewed-by: Ian Abbott <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/comedi/drivers.c

···
 			 "driver '%s' does not support attach using comedi_config\n",
 			 driv->driver_name);
 		module_put(driv->module);
-		ret = -ENOSYS;
+		ret = -EIO;
 		goto out;
 	}
 	dev->driver = driv;