Bump Verilator to v4.224

Created by: vighneshiyer

We're working on bumping Verilator to a modern release in Chipyard (https://github.com/ucb-bar/chipyard/pull/1205) and as part of that process we ran into a segfault when trying to simulate a Chipyard SoC with an Ariane core (which might be a Verilator bug).

To isolate the issue, I bumped Verilator in cva6 and verified that the simulation using your infrastructure works fine. This PR contains the minor changes required (see) if you all are interested. Feel free to close this otherwise.

Seemingly resolves (https://github.com/openhwgroup/cva6/issues/931) (vcd dumping works with the latest Verilator) and (https://github.com/openhwgroup/cva6/issues/934)