cpu_map: No longer ignore vmx- features in sync_qemu_features_i386.py

cpu_map: No longer ignore vmx- features in sync_qemu_features_i386.py

Some guest OSes require cpu features from the vmx-* family,
e.g. vmx-xsaves. Up to now, libvirt ignored these features as they
were not required yet. qemu does not automatically enable e.g.
"vmx-xsaves" when requesting "xsaves":

    qmp="qemu-kvm -machine accel=kvm -nodefaults -nographic -qmp stdio"
    $(qmp) <<-EOF | jq | grep "xsaves"
    { "execute": "qmp_capabilities" }
    {
      "execute": "query-cpu-model-expansion",
      "arguments": {
        "type": "full",
        "model": {
          "name": "Skylake-Client-v1",
          "props": { "xsaves": true }   `# set to "true" or "false"`
        }
      }
    }
    { "execute": "quit" }
    EOF

with xsaves "false":
    "xsaves": false,
    "vmx-xsaves": false,

with xsaves "true":
    "xsaves": true,
    "vmx-xsaves": false,

Stop ignoring vmx-* features and begin adding them to libvirt's
database.

Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>