mm/slab: Fix undefined init_cache_node_node() for NUMA and !SMP

mm/slab: Fix undefined init_cache_node_node() for NUMA and !SMP

sh/migor_defconfig:

    mm/slab.c: In function ‘slab_memory_callback’:
    mm/slab.c:1127:23: error: implicit declaration of function ‘init_cache_node_node’; did you mean ‘drain_cache_node_node’? [-Werror=implicit-function-declaration]
     1127 |                 ret = init_cache_node_node(nid);
	  |                       ^~~~~~~~~~~~~~~~~~~~
	  |                       drain_cache_node_node

The #ifdef condition protecting the definition of init_cache_node_node()
no longer matches the conditions protecting the (multiple) users.

Fix this by syncing the conditions.

Fixes: 76af6a054da40553 ("mm/migrate: add CPU hotplug to demotion #ifdef")
Reported-by: Randy Dunlap <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Geert Uytterhoeven <[email protected]>
Reviewed-by: John Paul Adrian Glaubitz <[email protected]>
Acked-by: Randy Dunlap <[email protected]>
Cc: <[email protected]>
Signed-off-by: Vlastimil Babka <[email protected]>