staging: comedi: addi_apci_16xx: board does not have a timer

The boards supported by this driver do not have a timer subdevice.
Remove the subdevice init for 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>