drm/amd/display: Code change for DML isolation

[why]
DML itself is SW only, putting the logic as part of resource makes it
hw dependent and thus impossible to compile separately from dc.
Separate compilation is critical for unit testing as well as bbox tool
development

[how]
create new dml wrapper.
Copy logic from the validation functions into dml wrapper as base
implementation. Dml wrapper has internal/static implementations
for all helpers, and does not reference other functions.
It may reference dc structures/types for convenience.

This change now has all the changes for DML isolation squashed into
one.

Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Jun Lei <jun.lei@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>