drm/amd/pm: Fix power limit query on aldebaran

Aldebaran doesn't have AC/DC power limits. Separate the implementation
from SMU13. Max power limit is queried from PPTable.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Kevin Wang <kevin1.wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>