staging: comedi: comedi_subdevice 'io_bits' should be an unsigned int

The 'io_bits' variable in the comedi_subdevice struct is a bitmask of
the input/output configuration of the the subdevice. It should be an
unsigned int to correctly represent this.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Frank Mori Hess: <fmhess@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/comedidev.h

@@ -78,7 +78,7 @@ struct comedi_subdevice {
 	unsigned runflags;
 	spinlock_t spin_lock;
 
-	int io_bits;
+	unsigned int io_bits;
 
 	unsigned int maxdata;	/* if maxdata==0, use list */
 	const unsigned int *maxdata_list;	/* list is channel specific */