mm: Add folio_put_refs()

This is like folio_put(), but puts N references at once instead of
just one.  It's like put_page_refs(), but does one atomic operation
instead of two, and is available to more than just gup.c.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>