staging: comedi: serial2002: return 0 after successful attach

A return value of >=0 indicates a successful attach to the comedi core.
Return 0 since that is more common in the kernel.

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/serial2002.c

@@ -806,7 +806,7 @@ static int serial2002_attach(struct comedi_device *dev,
 	s->range_table	= NULL;
 	s->insn_read	= serial2002_encoder_insn_read;
 
-	return 1;
+	return 0;
 }
 
 static void serial2002_detach(struct comedi_device *dev)