UBUNTU: SAUCE: cpu/speculation: Uninline and export CPU mitigations helpers

UBUNTU: SAUCE: cpu/speculation: Uninline and export CPU mitigations helpers

A kernel module may need to check the value of the "mitigations=" kernel
command line parameter as part of its setup when the module needs
to perform software mitigations for a CPU flaw. Uninline and export the
helper functions surrounding the cpu_mitigations enum to allow for their
usage from a module. Lastly, privatize the enum and cpu_mitigations
variable since the value of cpu_mitigations can be checked with the
exported helper functions.

Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
CVE-2018-12207

Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>