vts: fix some tunerhal vts fail without frontend device

PD#OTT-27646
bug:222020221

Problem:
some tunerhal vts fail without frontend device

Solution:
fix some logic errors without frontend device

verify:
ohm

Change-Id: I611a81400eb21bb52d59281f2266f3a95e015de9
Signed-off-by: junchao yuan <junchao.yuan@amlogic.com>
diff --git a/tv/tuner/1.0/vts/functional/FrontendTests.cpp b/tv/tuner/1.0/vts/functional/FrontendTests.cpp
index 5265f2d..22a4bf9 100644
--- a/tv/tuner/1.0/vts/functional/FrontendTests.cpp
+++ b/tv/tuner/1.0/vts/functional/FrontendTests.cpp
@@ -418,16 +418,18 @@
 
 void FrontendTests::getFrontendIdByType(FrontendType feType, uint32_t& feId) {
     ASSERT_TRUE(getFrontendIds());
-    ASSERT_TRUE(mFeIds.size() > 0);
-    for (size_t i = 0; i < mFeIds.size(); i++) {
-        ASSERT_TRUE(getFrontendInfo(mFeIds[i]));
-        if (mFrontendInfo.type != feType) {
-            continue;
+    if (mFeIds.size() > 0) {
+        for (size_t i = 0; i < mFeIds.size(); i++) {
+            ASSERT_TRUE(getFrontendInfo(mFeIds[i]));
+            if (mFrontendInfo.type != feType) {
+                continue;
+            }
+            feId = mFeIds[i];
+            return;
         }
-        feId = mFeIds[i];
-        return;
+    } else {
+        feId = INVALID_ID;
     }
-    feId = INVALID_ID;
 }
 
 void FrontendTests::tuneTest(FrontendConfig frontendConf) {