drm/amd/display: Fix FMT truncation programming

Switch the order of parameters being set for depth
and mode of truncation, as it previously was not correct

Signed-off-by: Mikita Lipski <mikita.lipski@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>