KVM: ia64: Enable virtio driver for ia64 in Kconfig

kvm/ia64 uses the virtio drivers to optimize its I/O subsytem.
Signed-off-by: NXiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

arch/ia64/kvm/Kconfig

@@ -46,4 +46,6 @@ config KVM_INTEL
 config KVM_TRACE
        bool
 
+source drivers/virtio/Kconfig
+
 endif # VIRTUALIZATION