fs: aio: use a folio in aio_setup_ring()

Use a folio throughout aio_setup_ring() to remove calls to compound_head(),
also use folio_end_read() to simultaneously mark the folio uptodate and
unlock it.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Link: https://lore.kernel.org/r/20240321131640.948634-2-wangkefeng.wang@huawei.com


Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>