btrfs: update the writepage tracepoint to take a folio

Willy is wanting to get rid of page->index, convert the writepage
tracepoint to take a folio so we can do folio->index instead of
page->index.

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