staging: comedi: addi_apci_1564: remove APCI1564_COUNTER[1234] defines

These defines don't add any significant clarity to the driver. Remove them.

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>