verilator: fix issue with parsing cli_parser
verilator: fix issue with parsing cli_parser

This fixes an error I was seeing:

  $ fusesoc run --target marocchino_tb --tool=icarus mor1kx-generic --elf-load /home/shorne/work/openrisc/or1k-tests/native/build/or1k/or1k-alignillegalinsn --pipeline=MAROCCHINO
  WARNING: Parse error. Ignoring file /home/shorne/work/openrisc/local-cores/mor1kx-generic/mor1kx-generic.core: Unknown item 'cli_parser in section Verilator'
  ERROR: 'mor1kx-generic' or any of its dependencies requires 'mor1kx-generic', but this core was not found

This seems to have been introduced by:

commit 022a596fdb1bd7383bd1e3eca992795e848c6095
Author: Olof Kindgren <olof.kindgren@gmail.com>
Date:   Fri Feb 22 22:59:33 2019 +0100

    Document tool options for all other backends

lowRISC/edalize,SymbiFlow/edalize,SymbiFlow/edalize,lowRISC/edalize