drm/amd/display: Don't allocate payloads if link lost

We should not allocate payloads if the link is lost until the link is retrained.
Some displays require this.

Signed-off-by: Alvin Lee <alvin.lee2@amd.com>
Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>