lib: sbi: Simplify timer platform operations

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>

lib/utils/timer/fdt_timer_clint.c

@@ -47,7 +47,4 @@ struct fdt_timer fdt_timer_clint = {
 	.cold_init = timer_clint_cold_init,
 	.warm_init = clint_warm_timer_init,
 	.exit = NULL,
-	.value = clint_timer_value,
-	.event_stop = clint_timer_event_stop,
-	.event_start = clint_timer_event_start,
 };