staging: comedi: make comedi_free_board_minor() static

`comedi_free_board_minor()` is now only called from the same .c file it
is defined in, so give it static linkage.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/comedi_fops.c

@@ -2342,7 +2342,7 @@ static void comedi_free_board_file_info(struct comedi_file_info *info)
 	}
 }
 
-void comedi_free_board_minor(unsigned minor)
+static void comedi_free_board_minor(unsigned minor)
 {
 	BUG_ON(minor >= COMEDI_NUM_BOARD_MINORS);
 	comedi_free_board_file_info(comedi_clear_minor(minor));

drivers/staging/comedi/comedi_internal.h

@@ -9,7 +9,6 @@
 int do_rangeinfo_ioctl(struct comedi_device *dev,
 		       struct comedi_rangeinfo __user *arg);
 int comedi_alloc_board_minor(struct device *hardware_device);
-void comedi_free_board_minor(unsigned minor);
 void comedi_release_hardware_device(struct device *hardware_device);
 int comedi_alloc_subdevice_minor(struct comedi_subdevice *s);
 void comedi_free_subdevice_minor(struct comedi_subdevice *s);