[hw/formal] Fix rtl_diff_all for rv_plic
[hw/formal] Fix rtl_diff_all for rv_plic

Now using rv_plic.sv from top_earlgrey directory.

lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan