forked from Mirrors/opensbi

Instead of having timer_value(), timer_event_start(), and timer_event_stop() callbacks in platform operations, it will be much simpler for timer driver to directly register these operations as device to the sbi_timer implementation. Signed-off-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Alistair Francis <alistair.francis@wdc.com>