staging: comedi: rtd520: hook up 8254 timer/counter subdevice

There is a standard 8254 Timer/Counter device on the board. Hook up
the subdevice for the user.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/staging/comedi/Kconfig b/drivers/staging/comedi/Kconfig
index 682987e..a5f2a3e 100644
--- a/drivers/staging/comedi/Kconfig
+++ b/drivers/staging/comedi/Kconfig
@@ -1064,6 +1064,7 @@
 
 config COMEDI_RTD520
 	tristate "Real Time Devices PCI4520/DM7520 support"
+	select COMEDI_8254
 	---help---
 	  Enable support for Real Time Devices PCI4520/DM7520