forked from Mirrors/opensbi

Add pmu_init() platform override, which will be used to register PMU device and populate event mappings. Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> Reviewed-by: Anup Patel <anup@brainfault.org>