slab: delete useless RED_INACTIVE and RED_ACTIVE

These seem useless since we use the SLUB_RED_INACTIVE and SLUB_RED_ACTIVE,
so just delete them, no functional change.

Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Chengming Zhou <chengming.zhou@linux.dev>
Reviewed-by: Christoph Lameter (Ampere) <cl@linux.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>