drm/amd/display: DPP DTO isn't update properly.

[Why]
before update dpp DTO, we check dppclks in context to determine it is
changed or not, but dppclks in context will be updated anyways after
flip is done, so compare dppclks in context will always get an equal
result.

[How]
Add pipe dpp clks in dccg and compare values between dccg and context.

Signed-off-by: Yongqiang Sun <yongqiang.sun@amd.com>
Reviewed-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>