BugLink: https://bugs.launchpad.net/bugs/1764956

IBRS in Ubuntu can be controlled dynamically from userspace. Make sure
the correct state is restored on VMEXIT.
Suggested-by: Gavin Guo <gavin.guo@canonical.com>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Acked-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Gavin Guo <gavin.guo@canonical.com>
Tested-by: Gavin Guo <gavin.guo@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>