Problem: The global mitigation knob mitigations=off does not turn off
X86_BUG_ITLB_MULTIHIT mitigation.

Fix: Turn off the mitigation when ITLB_MULTIHIT mitigation mode is
"auto" and mitigations are turned off globally via cmdline
mitigations=off.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>

CVE-2018-12207

[tyhicks Backport to 4.4
 - Minor context adjustment due to missing kvm_set_mmio_spte_mask()
 - kernel-parameters.txt is up one directory level]
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>