Add HAP feature to schema and documentation.
<pae/>
<acpi/>
<apic/>
+ <hap/>
</features>
...</pre>
<dd>ACPI is useful for power management, for example, with
KVM guests it is required for graceful shutdown to work.
</dd>
+ <dt><code>hap</code></dt>
+ <dd>Enable use of Hardware Assisted Paging if available in
+ the hardware.
+ </dd>
</dl>
<h3><a name="elementsTime">Time keeping</a></h3>
</element>
</define>
<!--
- A set of optional features: PAE, APIC and ACPI support
+ A set of optional features: PAE, APIC, ACPI, and HAP support
-->
<define name="features">
<optional>
<empty/>
</element>
</optional>
+ <optional>
+ <element name="hap">
+ <empty/>
+ </element>
+ </optional>
</interleave>
</element>
</optional>