Add TimeFilter test in Tuner VTS

Test: VtsHalTvTunerV1_0TargetTest
Bug: 150953857
Change-Id: I5509f4d368a44a7cb9bbe1b2499a4b4760b510b6
diff --git a/tv/tuner/1.0/default/Demux.cpp b/tv/tuner/1.0/default/Demux.cpp
index b74f6ec..7e1f5ac 100644
--- a/tv/tuner/1.0/default/Demux.cpp
+++ b/tv/tuner/1.0/default/Demux.cpp
@@ -93,9 +93,9 @@
 Return<void> Demux::openTimeFilter(openTimeFilter_cb _hidl_cb) {
     ALOGV("%s", __FUNCTION__);
 
-    sp<TimeFilter> timeFilter = new TimeFilter(this);
+    mTimeFilter = new TimeFilter(this);
 
-    _hidl_cb(Result::SUCCESS, timeFilter);
+    _hidl_cb(Result::SUCCESS, mTimeFilter);
     return Void();
 }