GpuService: add RootTargetPreparer to gpuservice_unittest

Fixes: 171732696
Test: gpuservice_unittest
Change-Id: I4342a5dc7c5a92c4b89e97c2b24a87e7d24793bb
diff --git a/services/gpuservice/tests/unittests/AndroidTest.xml b/services/gpuservice/tests/unittests/AndroidTest.xml
index 66f51c7..72976a8 100644
--- a/services/gpuservice/tests/unittests/AndroidTest.xml
+++ b/services/gpuservice/tests/unittests/AndroidTest.xml
@@ -18,6 +18,7 @@
         <option name="cleanup" value="true" />
         <option name="push" value="gpuservice_unittest->/data/local/tmp/gpuservice_unittest" />
     </target_preparer>
+    <target_preparer class="com.android.tradefed.targetprep.RootTargetPreparer" />
     <option name="test-suite-tag" value="apct" />
     <test class="com.android.tradefed.testtype.GTest" >
         <option name="native-test-device-path" value="/data/local/tmp" />