audio_device: Make AudioDeviceName constructor constexpr

These are used as read-only arrays, so we can make the data read-only
and available at compile-time.

Now constructing an AudioDevice no longer needs to initialize some
tables

src/audio_core/audio_out_manager.cpp

@@ -74,7 +74,7 @@ void Manager::BufferReleaseAndRegister() {
 
 u32 Manager::GetAudioOutDeviceNames(
     std::vector<AudioRenderer::AudioDevice::AudioDeviceName>& names) const {
-    names.push_back({"DeviceOut"});
+    names.emplace_back("DeviceOut");
     return 1;
 }