drm/amd/display: init dc_config before rest of DC init

[Why]
In some cases we want DC init to take in some config options

[How]
Init dc_config before rest of DC init

Signed-off-by: Anthony Koo <Anthony.Koo@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>