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

stable inclusion
from stable-v5.10.123
commit 001415e4e626403c9ff35f2498feb0021d0c8328
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I5D5RS
CVE: CVE-2022-21123,CVE-2022-21125,CVE-2022-21166

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-5.10.y&id=001415e4e626403c9ff35f2498feb0021d0c8328



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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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yipeng Zou <zouyipeng@huawei.com>
Reviewed-by: Zhang Jianhua <chris.zjh@huawei.com>
Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: Liao Chang <liaochang1@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>