Fix clang-tidy warnings in soundtrigger.

* Add explicit keyword to conversion constructors.
Bug: 28341362
* Use const reference type for read-only parameters.
Bug: 30407689
Test: build with WITH_TIDY=1

Change-Id: I28b251c99c78286a2da1e039df470a3f0bd8abe2
diff --git a/services/soundtrigger/SoundTriggerHwService.cpp b/services/soundtrigger/SoundTriggerHwService.cpp
index 9de6fe2..ad56e5d 100644
--- a/services/soundtrigger/SoundTriggerHwService.cpp
+++ b/services/soundtrigger/SoundTriggerHwService.cpp
@@ -163,7 +163,7 @@
 }
 
 
-void SoundTriggerHwService::detachModule(sp<Module> module)
+void SoundTriggerHwService::detachModule(const sp<Module>& module)
 {
     ALOGV("detachModule");
     AutoMutex lock(mServiceLock);