Staging: comedi: make comedi_reset_async_buf local to comedi core

No one outside of the comedi core calls this function, so don't export
it to the world.

Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Frank Mori Hess <fmhess@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/staging/comedi/internal.h b/drivers/staging/comedi/internal.h
index 4b6065a..7068a38 100644
--- a/drivers/staging/comedi/internal.h
+++ b/drivers/staging/comedi/internal.h
@@ -1,3 +1,4 @@
 
 int comedi_alloc_board_minor(struct device *hardware_device);
 void comedi_free_board_minor(unsigned minor);
+void comedi_reset_async_buf(struct comedi_async *async);