Extend Spyglass lint to lint/lint_rtl goal

[colluca]

The Spyglass lint would previously only run the DesignRead goal.
This PR extends it to the lint/lint_rtl goal (which includes the DesignRead goal).

TODO:

• merge after Cleanup module port and parameter lists #311

[phsauter]

I will have to think about whether I like the blocking assignments in clk_int_div, as I understand it they are only needed for simulation purposes so we might want to have explicit synthesis and simulation versions there.