staging: comedi: remove comedi_board()

All calls to the inline function `comedi_board()` in "comedidev.h" have
been removed, so remove the function.
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/comedidev.h

@@ -269,11 +269,6 @@ struct comedi_device {
 	void (*close)(struct comedi_device *dev);
 };
 
-static inline const void *comedi_board(const struct comedi_device *dev)
-{
-	return dev->board_ptr;
-}
-
 /*
  * function prototypes
  */