UBUNTU: SAUCE: Fix spec_ctrl support in KVM

UBUNTU: SAUCE: Fix spec_ctrl support in KVM

CVE-2017-5753
CVE-2017-5715

Initial change was missing code to correctly mask EDX bits of cpuid
level 7.0.

Fixes: 8339cae ("KVM: x86: Add speculative control CPUID support for guests")
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Acked-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>