mm/sl[aou]b: Get rid of __kmem_cache_destroy

mm/sl[aou]b: Get rid of __kmem_cache_destroy

What is done there can be done in __kmem_cache_shutdown.

This affects RCU handling somewhat. On rcu free all slab allocators do
not refer to other management structures than the kmem_cache structure.
Therefore these other structures can be freed before the rcu deferred
free to the page allocator occurs.

Reviewed-by: Joonsoo Kim <[email protected]>
Signed-off-by: Christoph Lameter <[email protected]>
Signed-off-by: Pekka Enberg <[email protected]>