misc: add assert to check the missing of CLOS MASK

The current UI there is an issue which have not sync and save the VMs
to RDT element, these issue will cause the missing of num_pclosids and
the HV can't start.

This patch add assert to check the the missing of CLOS MASK.
The UI issue will be fix by another patch.

Tracked-On: #6690
Signed-off-by: Chenli Wei <chenli.wei@linux.intel.com>

misc/config_tools/schema/checks/rdt_support.xsd

@@ -53,4 +53,13 @@ This error cannot be fixed by adjusting the configuration. Report a `GitHub issu
     </xs:annotation>
   </xs:assert>
 
+  <xs:assert test="every $vm_name in //vm/name satisfies
+                  if (//RDT_ENABLED = 'y')
+                  then count(//POLICY/VM[text() = $vm_name]) > 0
+                  else true()">
+    <xs:annotation acrn:severity="error" acrn:report-on="/acrn-config/hv/CACHE_REGION">
+      <xs:documentation>Need config the CLOS MASK for VM '{$vm_name}''.</xs:documentation>
+    </xs:annotation>
+  </xs:assert>
+
 </xs:schema>