forked from Mirrors/opensbi

We add platform specific extensions_init() callback which allows platforms to populate HART extensions for each HART. For example, the generic platform can populate HART extensions from HART ISA string described in DeviceTree. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com>