Fix/suppress cmds/lshal google-explicit-constructor warnings

* Add explicit to conversion constructors/operators
* Use NOLINT or NOLINTNEXTLINE to suppress warnings on intended converters

Bug: 28341362
Test: make with WITH_TIDY=1 DEFAULT_GLOBAL_TIDY_CHECKS=-*,google-explicit-constructor
Change-Id: I67a59b0051b5550ea135a91664bf03995e94eb75
diff --git a/cmds/lshal/Timeout.h b/cmds/lshal/Timeout.h
index 58119a6..46d8177 100644
--- a/cmds/lshal/Timeout.h
+++ b/cmds/lshal/Timeout.h
@@ -29,7 +29,7 @@
 
 class BackgroundTaskState {
 public:
-    BackgroundTaskState(std::function<void(void)> &&func)
+    explicit BackgroundTaskState(std::function<void(void)> &&func)
             : mFunc(std::forward<decltype(func)>(func)) {}
     void notify() {
         std::unique_lock<std::mutex> lock(mMutex);