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
1 file changed