Documentation: Correct the possible MDS sysfs values

Adjust the last two rows in the table that display possible values when
MDS mitigation is enabled. They both were slightly innacurate.

In addition, convert the table of possible values and their descriptions
to a list-table. The simple table format uses the top border of equals
signs to determine cell width which resulted in the first column being
far too wide in comparison to the second column that contained the
majority of the text.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

CVE-2018-12126
CVE-2018-12127
CVE-2018-12130
CVE-2019-11091

(cherry picked from commit ea01668f)
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Acked-by: Juerg Haefliger <juerg.haefliger@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

Documentation/admin-guide/hw-vuln/mds.rst

@@ -95,22 +95,19 @@ mitigations are active. The relevant sysfs file is:
 
 The possible values in this file are:
 
-  =========================================   =================================
-  'Not affected'				The processor is not vulnerable
-
-  'Vulnerable'					The processor is vulnerable,
-						but no mitigation enabled
-
-  'Vulnerable: Clear CPU buffers attempted'	The processor is vulnerable but
-						microcode is not updated.
-						The mitigation is enabled on a
-						best effort basis.
-						See :ref:`vmwerv`
-
-  'Mitigation: CPU buffer clear'		The processor is vulnerable and the
-						CPU buffer clearing mitigation is
-						enabled.
-  =========================================   =================================
+  .. list-table::
+
+     * - 'Not affected'
+       - The processor is not vulnerable
+     * - 'Vulnerable'
+       - The processor is vulnerable, but no mitigation enabled
+     * - 'Vulnerable: Clear CPU buffers attempted, no microcode'
+       - The processor is vulnerable but microcode is not updated.
+
+         The mitigation is enabled on a best effort basis. See :ref:`vmwerv`
+     * - 'Mitigation: Clear CPU buffers'
+       - The processor is vulnerable and the CPU buffer clearing mitigation is
+         enabled.
 
 If the processor is vulnerable then the following information is appended
 to the above information: