mm/slub: Refactor note_cmpxchg_failure for better readability

Use IS_ENABLED() and standard if-else to make the code clearer.

Signed-off-by: Ye Liu <liuye@kylinos.cn>
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Reviewed-by: Christoph Lameter (Ampere) <cl@gentwo.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>