mm/hugetlb_cgroup: switch to the new cftypes

mm/hugetlb_cgroup: switch to the new cftypes

The previous patch has already reconstructed the cftype attributes based
on the templates and saved them in dfl_cftypes and legacy_cftypes.  then
remove the old procedure and switch to the new cftypes.

Link: https://lkml.kernel.org/r/20240612092409.2027592-4-xiujianfeng@huawei.com
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>