filemap: Use a folio in filemap_map_pages

Saves 61 bytes due to fewer calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
This commit is contained in:
Matthew Wilcox (Oracle) 2021-03-12 23:46:45 -05:00
commit 820b05e92b