Reduce default severity of Verific messages that produce warnings on commonly used coding styles

[nakengelhardt]

In common with most EDA tools, Verific produces warnings on a lot of benign, commonly used (System-)Verilog coding styles. This is not in line with the Yosys philosophy, where warnings usually indicate a significant problem in the design that is likely to result in missynthesis.

The following messages should have their default severity decreased from WARNING to INFO:

• VERIFIC-WARNING [VERI-1209] foo.sv:98: expression size 7 truncated to fit in target size 6
• VERIFIC-WARNING [VERI-1142] foo.sv:55: system task 'display' is ignored for synthesis
• VERIFIC-WARNING [VERI-2418] foo.svh:503: parameter 'all_cfgs_gp' declared inside package 'bp_common_pkg' shall be treated as localparam
• (please suggest further nominations as you encounter them)

As a motivating data point, using verific -set-info on the first three reduced the warning load from 176 mostly useless warnings to 10 very relevant warnings on the BlackParrot core.