forked from Mirrors/opensbi

This patch extends our SBI ecall implementation to allow dynamic registration of various SBI extensions. Using this dynamic registration we can break-up SBI ecall implementation into multiple files and even register experimental/custom SBI extensions from platform code. Signed-off-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Atish Patra <atish.patra@wdc.com>