drm/amd/display: Fix MST Multi-Stream Not Lighting Up on dcn35

dcn35 misses .enable_symclk_se hook that makes MST DSC
not functional when having multiple FE clk to be enabled.

Reviewed-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Acked-by: Roman Li <roman.li@amd.com>
Signed-off-by: Fangzhi Zuo <jerry.zuo@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>