Fix bug for none fe test case

Test: atest VtsHalTvTunerV1_0TargetTest

bug: 182519645
Change-Id: I5deca5fe7f4f023cbadaf54f894657c1c6efe38a
Merged-In: I86458142ba4155274594a793eb939567bea24734
diff --git a/tv/tuner/1.0/vts/functional/DescramblerTests.cpp b/tv/tuner/1.0/vts/functional/DescramblerTests.cpp
index 2e27475..67f6bae 100644
--- a/tv/tuner/1.0/vts/functional/DescramblerTests.cpp
+++ b/tv/tuner/1.0/vts/functional/DescramblerTests.cpp
@@ -53,12 +53,15 @@
         return failure();
     }
 
-    auto status = mCas->setSessionPrivateData(sessionId, hidlPvtData);
-    if (status != android::hardware::cas::V1_0::Status::OK) {
-        ALOGW("[vts] Failed to set session private data");
-        mCas->closeSession(sessionId);
-        return failure();
+    if (hidlPvtData.size() > 0) {
+        auto status = mCas->setSessionPrivateData(sessionId, hidlPvtData);
+        if (status != android::hardware::cas::V1_0::Status::OK) {
+            ALOGW("[vts] Failed to set session private data");
+            mCas->closeSession(sessionId);
+            return failure();
+        }
     }
+
     return success();
 }