buffer: convert grow_dev_page() to use a folio

Get a folio from the page cache instead of a page, then use the folio API
throughout.  Removes a few calls to compound_head() and may be needed to
support block size > PAGE_SIZE.

Link: https://lkml.kernel.org/r/20230612210141.730128-11-willy@infradead.org


Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>