Staging: comedi: addi_apci_3120: Remove unnecessary if

Remove the if condition, as the code inside the if condition is
commented and does not have any FIXME or TODO comment.

Signed-off-by: Shraddha Barke <shraddha.6596@gmail.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>