nfs: Convert to free_folio

Add a wrapper that converts back from the folio to the page.  This
entire file needs to be converted to use folios, but that's a
task for a different set of patches.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2022-05-01 08:00:56 -04:00
commit aa5dc8c461