drm/amd/display: use even ODM slice width for two pixels per container

[why]
When optc uses two pixel per container, each ODM slice width must be an
even number.

[how]
If ODM slice width is odd number increase it by 1.

Reviewed-by: Dillon Varone <dillon.varone@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>