drm/amd/display: Enable fast update on blendTF change

[Why]
Full update is not required on surface blend TF change.

[How]
Update full_update_required condition.

Reviewed-by: Aric Cyr <aric.cyr@amd.com>
Acked-by: Hersen Wu <hersenxs.wu@amd.com>
Signed-off-by: Ilya Bakoulin <ilya.bakoulin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>