staging: comedi: ni_670x: removve unused 'ao_bits'

All the NI 670x boards have 16-bit anaolog output DACs. The
'ao_bits' in the boardinfo is not used so remove it.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/ni_670x.c

@@ -64,7 +64,6 @@ struct ni_670x_board {
 	const char *name;
 	unsigned short dev_id;
 	unsigned short ao_chans;
-	unsigned short ao_bits;
 };
 
 static const struct ni_670x_board ni_670x_boards[] = {
@@ -72,17 +71,14 @@ static const struct ni_670x_board ni_670x_boards[] = {
 		.name		= "PCI-6703",
 		.dev_id		= 0x2c90,
 		.ao_chans	= 16,
-		.ao_bits	= 16,
 	}, {
 		.name		= "PXI-6704",
 		.dev_id		= 0x1920,
 		.ao_chans	= 32,
-		.ao_bits	= 16,
 	}, {
 		.name		= "PCI-6704",
 		.dev_id		= 0x1290,
 		.ao_chans	= 32,
-		.ao_bits	= 16,
 	},
 };