staging: comedi: amplc_pci230: no need to initialize named members to zero

The members of the elements of `pci230_boards[]` that are not explicitly
named in their initializers will be initialized to 0 automatically, so
there is no need to initialize them to 0 explicitly.

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