mm/slub: remove forced_order parameter in calculate_sizes

Since commit 32a6f409 ("mm, slub: remove runtime allocation order
changes"), forced_order is always -1. Remove this unneeded parameter
to simplify the code.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Link: https://lore.kernel.org/r/20220309092036.50844-1-linmiaohe@huawei.com