drm/amd/display: ACPI Re-timer Programming

drm/amd/display: ACPI Re-timer Programming

[Why]
We must implement an ACPI re-timer programming interface and notify
ACPI driver whenever a PHY transition is about to take place.

Because some trace lengths on certain platforms are very long,
then a re-timer may need to be programmed whenever a PHY transition
takes place. The implementation of this re-timer programming interface
will notify ACPI driver that PHY transition is taking place and it
will trigger the re-timer as needed.

First we need to gather retimer information from ACPI interface.

Then, in the PRE case, the re-timer interface needs to be called before we call
transmitter ENABLE.
In the POST case, it has to be called after we call transmitter DISABLE.

[How]
Implemented ACPI retimer programming interface.

Reviewed-by: Alvin Lee <alvin.lee2@amd.com>
Signed-off-by: Rafal Ostrowski <rostrows@amd.com>
Signed-off-by: Zaeem Mohamed <zaeem.mohamed@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>