Mismatch between `max_trace_verbosity` and `vtrace_fmt!` codegen output

[rw1nkler]

Describe the bug

Even though one can specify a high value for "max_trace_verbosity in the codegen options.
Only vtrace_fmt! that use log level u32:0 are emited in SytemVerilog.

To Reproduce

I created a small example to reproduce the problem.
It is available on the following branch:

• https://github.com/antmicro/xls/tree/vtrace_fmt

Steps to reproduce the behavior:

1. Get the code of the example
2. execute bazel build //xls/examples:vtrace_fmt_verilog
3. obsrve that only a $display("Verbosity level 0"); is avaliable in the generated verilog

Expected behavior
The verilog should also contain $display("Verbosity level 10"); since max_trace_verbosity was set to 100 for the //xls/examples:vtrace_fmt_verilog target