ufs: use ufs_get_locked_folio() in ufs_alloc_lastblock()

Switch to the folio APIs, saving one folio->page->folio conversion.

Link: https://lkml.kernel.org/r/20231016201114.1928083-25-willy@infradead.org


Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>