mm: reimplement compound_order()

Make compound_order() use struct folio.  It can't be turned into a wrapper
around folio_order() as a page can be turned into a tail page between a
check in compound_order() and the assertion in folio_test_large().

Link: https://lkml.kernel.org/r/20230111142915.1001531-17-willy@infradead.org


Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>