forked from Mirrors/opensbi

Currently, the mhpmevent CSRs are untouched during hart init during cold/warm boot. Ideally, we should clear out all the bits except overflow and MINH bit. That is required to disable overflow interrupt and inhibit counting in M-mode to avoid any spurious interrupts before perf start. Signed-off-by: Atish Patra <atishp@rivosinc.com> Reviewed-by: Anup Patel <anup@brainfault.org>