Audio policy config: Device port (type,address) must be unique

Device port are not identified by names but by their type and address
and the module they are in.

As a result, enforce this constraint in the XSD. Violating it results in
a policy parsing crash.

Bug: 69442986
Test: xmllint invalidates an XML with two devices of the same type
      and address
Test: vts-tradefed run commandAndExit vts --module VtsHalAudioV2_0Target -t CheckConfig.audioPolicyConfigurationValidation
Change-Id: I84245f0fa80fef786a002c98073c166b6aaf2be4
Signed-off-by: Kevin Rocard <krocard@google.com>

audio/2.0/config/audio_policy_configuration.xsd

@@ -148,6 +148,11 @@
                     <xs:selector xpath="devicePorts/devicePort"/>
                     <xs:field xpath="@tagName"/>
                 </xs:key>
+                <xs:unique name="devicePortUniqueness">
+                    <xs:selector xpath="devicePorts/devicePort"/>
+                    <xs:field xpath="@type"/>
+                    <xs:field xpath="@address"/>
+                </xs:unique>
                 <xs:keyref name="defaultOutputDeviceRef" refer="devicePortNameKey">
                     <xs:selector xpath="defaultOutputDevice"/>
                     <xs:field xpath="."/>
@@ -419,7 +424,7 @@
                     <xs:attribute name="tagName" type="xs:token" use="required"/>
                     <xs:attribute name="type" type="audioDevice" use="required"/>
                     <xs:attribute name="role" type="role" use="required"/>
-                    <xs:attribute name="address" type="xs:string" use="optional"/>
+                    <xs:attribute name="address" type="xs:string" use="optional" default=""/>
                 </xs:complexType>
                 <xs:unique name="devicePortProfileUniqueness">
                     <xs:selector xpath="profile"/>