drm/amd/display: Pass debug watermarks through to DCN35 DML2

[Why]
The DC debug options currently do not function for dynamically adjusting
our watermarks.

[How]
Hook them up before passing them to DML2.
Also make sure we're using dc->bb_overrides since dc->debug isn't
populated during dc_construct.

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: Michael Strauss <michael.strauss@amd.com>
Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Acked-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>