drm/amd/display: Refactor SDR cursor boosting in HDR mode

[Why]
Cursor boosting is done via CNVC_CUR register which is DPP, not HUBP
Previous commit was implementing it in HUBP functions,
and also breaking diags tests.

[How]
1. Undo original commit as well as Eric's diags test fix, almost completely
2. Move programming to DPP and call via new dc_stream function
3. Also removing cur_rom_en from dpp_cursor_attributes and programming
as part of normal cursor attributes as it depends on cursor color format

Signed-off-by: Krunoslav Kovac <Krunoslav.Kovac@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>