slab: Remove folio references from kfree_rcu_sheaf()

slab: Remove folio references from kfree_rcu_sheaf()

In preparation for splitting struct slab from struct page and struct
folio, remove mentions of struct folio from this function.  Since
we don't need to handle large kmalloc objects specially here, we
can just use virt_to_slab().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20251113000932.1589073-12-willy@infradead.org
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>