Remove unecessary include that no longer exists

I11496e4c3dd6d0d43f635886b46609cb8e430efc removed
hidl/IServiceManager.h, remove it from service.cpp.

Test: m -j android.hardware.audio@2.0-service
Change-Id: I9e45345b345acb1cc15343c889361c2775933cc3
diff --git a/audio/2.0/default/service.cpp b/audio/2.0/default/service.cpp
index f254512..39708c2 100644
--- a/audio/2.0/default/service.cpp
+++ b/audio/2.0/default/service.cpp
@@ -19,7 +19,6 @@
 #include <hwbinder/IInterface.h>
 #include <hwbinder/IPCThreadState.h>
 #include <hwbinder/ProcessState.h>
-#include <hidl/IServiceManager.h>
 #include <utils/Errors.h>
 #include <utils/Log.h>
 #include <utils/Looper.h>