If a standard event was not found in the list of events that are handled
by harts but belongs to the standard event list defined by the
specification, return SBI_ENOTSUPP. Without that, we can not
distinguish a non implemented standard event from a non valid one.
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>