x86/speculation/mmio: Add sysfs reporting for Processor MMIO Stale Data

stable inclusion
from stable-v4.19.248
commit f2983fbba1cccac611d4966277f0336374fad0be
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I5D5RS


CVE: CVE-2022-21123,CVE-2022-21125,CVE-2022-21166

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

commit 8d50cdf8 upstream

Add the sysfs reporting file for Processor MMIO Stale Data
vulnerability. It exposes the vulnerability and mitigation state similar
to the existing files for the other hardware vulnerabilities.

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yipeng Zou <zouyipeng@huawei.com>
Reviewed-by: Zhang Jianhua <chris.zjh@huawei.com>
Reviewed-by: Liao Chang <liaochang1@huawei.com>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>