misc: add assert to check the RTVM CPU affinity

The current ACRN Configurator have no warning when the user set CPU zero
to RTVM.

This patch add an assert to check the above.

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

misc/config_tools/schema/checks/cpu_assignment.xsd

@@ -39,4 +39,11 @@
     </xs:annotation>
   </xs:assert>
 
+  <xs:assert test="every $vm in /acrn-config/vm[vm_type = 'RTVM'] satisfies
+                   count($vm//pcpu_id[./text() = '0']) = 0">
+    <xs:annotation acrn:severity="error" acrn:report-on="$vm//cpu_affinity">
+      <xs:documentation>The CPU 0 can't assign to RTVM {$vm/name/text()}.</xs:documentation>
+    </xs:annotation>
+  </xs:assert>
+
 </xs:schema>