[Why]
Populate dtbclk values from bwparams for dcn302, dcn303.

[How]
dtbclk values are fetched from bandwidthparams for all DPM levels and
for DPM levels where smu returns 0, previous level values are reported.
Reviewed-by: Roman Li <Roman.Li@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Bindu Ramamurthy <bindu.r@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>