jbd2: Convert jbd2_journal_try_to_free_buffers to take a folio

Also convert it to return a bool since it's called from release_folio().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jeff Layton <jlayton@kernel.org>