[Why]
When system is in Z10 HPD interrupts cannot fire, we may miss display
configuration changes.

[How]
When Zstate is enabled, if DMUB indicate DCN has lost power, do a
complete detection periodically.
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Mikita Lipski <mikita.lipski@amd.com>
Signed-off-by: Eric Yang <Eric.Yang2@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>