Fix google-explicit-constructor warnings.

Bug: 28341362
Change-Id: I625fbab25f16282c2ea929cd16283d9d146fa17b
diff --git a/media/utils/ISchedulingPolicyService.cpp b/media/utils/ISchedulingPolicyService.cpp
index f55bc02..f5bfe20 100644
--- a/media/utils/ISchedulingPolicyService.cpp
+++ b/media/utils/ISchedulingPolicyService.cpp
@@ -32,7 +32,7 @@
 class BpSchedulingPolicyService : public BpInterface<ISchedulingPolicyService>
 {
 public:
-    BpSchedulingPolicyService(const sp<IBinder>& impl)
+    explicit BpSchedulingPolicyService(const sp<IBinder>& impl)
         : BpInterface<ISchedulingPolicyService>(impl)
     {
     }