slub: use N_NORMAL_MEMORY in can_free_to_pcs to handle remote frees

slub: use N_NORMAL_MEMORY in can_free_to_pcs to handle remote frees

Memory hotplug now keeps N_NORMAL_MEMORY up to date correctly, so make
can_free_to_pcs() use it.

As a result, when freeing objects on memoryless nodes, or on nodes that
have memory but only in ZONE_MOVABLE, the objects can be freed to the
sheaf instead of going through the slow path.

Signed-off-by: Hao Li <hao.li@linux.dev>
Acked-by: Harry Yoo (Oracle) <harry@kernel.org>
Acked-by: David Rientjes <rientjes@google.com>
Link: https://patch.msgid.link/20260403073958.8722-1-hao.li@linux.dev
Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>