drm/amd/display: Fix MPCC 1DLUT programming

[Why]
Wrong function is used to translate LUT values to HW format, leading to
visible artifacting in some cases.

[How]
Use the correct cm3_helper function.

Cc: stable@vger.kernel.org # 6.1+
Reviewed-by: Krunoslav Kovac <krunoslav.kovac@amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Ilya Bakoulin <ilya.bakoulin@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>