drm/amd/display: Add a new flag for replay low hz

[Why & How]
Add a new flag in replay_config to indicate the replay
low hz status.

Reviewed-by: Allen Li <allen.li@amd.com>
Signed-off-by: Robin Chen <robin.chen@amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>