qemux86-64: Support for KVM, paravirt and virtio added

qemux86-64: Support for KVM, paravirt and virtio added

    KVM, paravirtualization and virtio drivers are now activated
    in runqemu using the kvm option flag for qemux86-64.
    Host CPU features are also exported to guest OS (Yocto Linux).
    Usage example: runqemu qemux86-64 core-image-x11 kvm

    Implements [YOCTO #2550].

(From OE-Core rev: cbb6431b3ee9128ea15c9ae0a19e7d2998ffc561)

Signed-off-by: Cristian Iorga <cristian.iorga@intel.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>