arch-riscv,dev: Add PLIC abstract class to support multiple PLIC
implementation

We should create PLIC abstract and have common interface to let
HiFive platform send and clear interrupt to variable type of PLIC

Change-Id: Ic3a2ffc2a2a002540b400c70c85c3495fa838f2a
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/68197
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Yu-hsin Wang <yuhsingw@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
4 files changed