btrfs: convert end_page_read() to take a folio

btrfs: convert end_page_read() to take a folio

We have this helper function to set the page range uptodate once we're
done reading it, as well as run fsverity against it.  Half of these
functions already take a folio, just rename this to end_folio_read and
then rework it to take a folio instead, and update everything
accordingly.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>