staging: comedi: addi_apci_1564: remove check for timer subdevice

The only board served by this driver always has a timer, so we can init
the timer subdevice without checking first.

The boardinfo about the timer can also be removed and the data used
directly.

Signed-off-by: Chase Southwood <chase.southwood@gmail.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>