Although the current code isn't wrong as far as I can tell, it would be
better to initialize the lognest_name_length variable when it is
declared to avoid a build warning with older Verilator versions.
DPI access is suggested and more generic than Verilator direct signal
access. This changes the access to the performance counters from the
Verilator testbench to use DPI instead of directly accessing the
array.
Signed-off-by: Stefan Wallentowitz <stefan.wallentowitz@hm.edu>