audio: Remove unnecessary std::move

Moving a temporary object prevents copy elision, and could reduce
performance.

This fixes -Wpessimizing-move compiler warning.

Test: presubmit
Bug: 154270751
Change-Id: Idb1a4abf4da9eb6dbe1e9a8fd66461d60985c8e1
diff --git a/audio/aidl/default/EffectMain.cpp b/audio/aidl/default/EffectMain.cpp
index a300cfd..7a6141a 100644
--- a/audio/aidl/default/EffectMain.cpp
+++ b/audio/aidl/default/EffectMain.cpp
@@ -38,7 +38,7 @@
             candidatePath.append(apexName).append("/etc/").append(kDefaultConfigName);
             LOG(DEBUG) << __func__ << " effect lib path " << candidatePath;
             if (access(candidatePath.c_str(), R_OK) == 0) {
-                return std::move(candidatePath);
+                return candidatePath;
             }
         }
     } else {