mm: memory-failure: move sysctl register in memory_failure_init()

There is already a memory_failure_init(), don't add a new initcall, move
register_sysctl_init() into it to cleanup a bit.

Link: https://lkml.kernel.org/r/20230508114128.37081-2-wangkefeng.wang@huawei.com


Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>