lib: utils: atcsmu: Add Andes System Management Unit support

This patch adds atcsmu support for Andes AE350 platforms. The SMU
provides system management capabilities, including clock, reset
and power control based on power domain partitions.

Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Anup Patel <anup@brainfault.org>