dcache: rename dc_ signals to dbus_
icache: fix verilator circular logic warning on ibus_req_o

no logical change, the removed mem_req signal was only
asserted during refill
icache: fix verilator circular logic warning on cpu_ack_o

this also completely remove the disabled refill_match
logic, since it is now conceptually broken anyway and needs
to be reworked.
dcache: fix verilator circular logic warning on cpu_err_o
dcache: fix verilator circular logic warning on cpu_ack_o
dcache: fix verilator circular logic warning on dbus_req_o
dcache: fix verilator WIDTH warning on start_adr
icache: fix verilator warning about incomplete case
cappuccino/fetch: fix verilator warning about incomplete case
cappuccino/fetch: fix verilator COMBDLY warning on fetch_valid
execute_alu: add verilator lint_off/lint_on around feature parms