Return SUCCESS in scan for ATSC

This is for a CTS test case

Bug: 150952758
Test: atest android.media.tv.tuner.cts.TunerTest
Change-Id: I8761fec6af392e4f2d18bc38760effcae2aec273
diff --git a/tv/tuner/1.0/default/Frontend.cpp b/tv/tuner/1.0/default/Frontend.cpp
index 2cff9be..6565746 100644
--- a/tv/tuner/1.0/default/Frontend.cpp
+++ b/tv/tuner/1.0/default/Frontend.cpp
@@ -81,6 +81,9 @@
 Return<Result> Frontend::scan(const FrontendSettings& settings, FrontendScanType type) {
     ALOGV("%s", __FUNCTION__);
 
+    if (mType == FrontendType::ATSC) {
+        return Result::SUCCESS;
+    }
     if (mType != FrontendType::DVBT) {
         return Result::UNAVAILABLE;
     }