drm/amd/display: add primary pipe check when building slice table for dcn3x

[why]
There is a corner use case where the same plane pointer can be added into
dc state twice. In addition to plane state pointer check we also need to match
primary pipe before identifying the same plane.

Reviewed-by: Dillon Varone <dillon.varone@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>