Static.h: include what you use.

Removed transitive dependencies on libutils types.

Bug: 35363681
Test: pass
Change-Id: Id32a089d96930e717b420a8d48831be426b45009
diff --git a/transport/include/hidl/Static.h b/transport/include/hidl/Static.h
index d62d675..04b1729 100644
--- a/transport/include/hidl/Static.h
+++ b/transport/include/hidl/Static.h
@@ -21,7 +21,8 @@
 #include <android/hidl/manager/1.0/IServiceManager.h>
 #include <hidl/ConcurrentMap.h>
 #include <hwbinder/IBinder.h>
-#include <utils/threads.h>
+#include <utils/StrongPointer.h>
+#include <utils/Mutex.h>
 
 namespace android {
 namespace hardware {