mm: add __folio_batch_release()

This performs the same role as __pagevec_release(), ie skipping the check
for batch length of 0.

Link: https://lkml.kernel.org/r/20230621164557.3510324-3-willy@infradead.org


Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>