mm/kfence: print disabling or re-enabling message

mainline inclusion
from mainline-v5.19-rc1
commit 83d7d04f
category: bugfix
bugzilla: 187071, https://gitee.com/openeuler/kernel/issues/I5DLA7
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=83d7d04f9d2ef354858b2a8444aee38e41ec1699

--------------------------------

By printing information, we can friendly prompt the status change
information of kfence by dmesg and record by syslog.

Also, set kfence_enabled to false only when needed.

Link: https://lkml.kernel.org/r/20220518073105.3160335-1-liu.yun@linux.dev


Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Co-developed-by: Marco Elver <elver@google.com>
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Conflicts:
	mm/kfence/core.c
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>