drm/amd/display: Fixing hubp programming of 3dlut fast load

[why]
HUBP needs to know the size of the lut's destination in MPC.
This is currently defaulted to 17, and needs to be set for specific
lut size.

[how]
Define and apply the missing hubp field. Taking this opportunity
to consolidate the programming of 3dlut into a hubp and mpc function.

Reviewed-by: Krunoslav Kovac <krunoslav.kovac@amd.com>
Signed-off-by: Reza Amini <reza.amini@amd.com>
Signed-off-by: Roman Li <roman.li@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>