drm/amd/display: Allow clock lower on dce100

dce100 was set to always pass safe_to_lower = false
to the clock manager

Thus, on suspend the clocks were not being set to 0
which is incorrect behaviour

This was causing s3 resume to blackscreen on intel
CPUs with dce100 GPUs attached

(Note that the hash in this Fixes: tag is the hash on Alex's tree)
Fixes: ae7d8aeb38d7 ("drm/amd/display: remove safe_to_lower flag from dc, use 2 functions instead")

Signed-off-by: David Francis <David.Francis@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>