drm/amd/display: Add support for Panel Replay on DP1 eDP (panel_inst=1)

[why & how]
DP1 eDP is still considered a single-eDP case and should support Panel Replay.
Modify secondary eDP policy to reflect this and update Replay state accordingly.

Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Signed-off-by: Ovidiu Bunea <Ovidiu.Bunea@amd.com>
Signed-off-by: Ivan Lipski <ivan.lipski@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>