mm/slub.c: replace kmem_cache->cpu_partial with wrapped APIs

There are slub_cpu_partial() and slub_set_cpu_partial() APIs to wrap
kmem_cache->cpu_partial.  This patch will use the two APIs to replace
kmem_cache->cpu_partial in slub code.

Signed-off-by: chenqiwu <chenqiwu@xiaomi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/1582079562-17980-1-git-send-email-qiwuchen55@gmail.com


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>