drm/amd/display: Revert "Directly retrain link from debugfs"

drm/amd/display: Revert "Directly retrain link from debugfs"

commit 1131cadfd7563975f3a4efcc6f7c1fdc872db38b upstream.

This reverts commit f5b6a20c7ef40599095c796b0500d842ffdbc639.

This patch broke new settings from taking effect. Hotplug is
required for new settings to take effect.

Reviewed-by: Mikita Lipski <mikita.lipski@amd.com>
Acked-by: Mikita Lipski <mikita.lipski@amd.com>
Signed-off-by: Anson Jacob <Anson.Jacob@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>