Fix/suppress google-explicit-constructor warnings

* Add explicit to conversion constructors/operators

Bug: 28341362
Test: make with WITH_TIDY=1 DEFAULT_GLOBAL_TIDY_CHECKS=-*,google-explicit-constructor
Change-Id: I815a5282f1fc0d308835988f40efb666fe06d118
diff --git a/cmds/dumpsys/dumpsys.h b/cmds/dumpsys/dumpsys.h
index 84f3b02..c48a1e9 100644
--- a/cmds/dumpsys/dumpsys.h
+++ b/cmds/dumpsys/dumpsys.h
@@ -26,7 +26,7 @@
 
 class Dumpsys {
   public:
-    Dumpsys(android::IServiceManager* sm) : sm_(sm) {
+    explicit Dumpsys(android::IServiceManager* sm) : sm_(sm) {
     }
     /**
      * Main entry point into dumpsys.