output/Internal: remove mutex code from Enable() and Disable()

src/output/Internal.cxx

@@ -32,7 +32,6 @@ void
 AudioOutput::Enable()
 {
 	try {
-		const ScopeUnlock unlock(mutex);
 		ao_plugin_enable(*this);
 	} catch (const std::runtime_error &e) {
 		std::throw_with_nested(FormatRuntimeError("Failed to enable output \"%s\" [%s]",
@@ -43,7 +42,6 @@ AudioOutput::Enable()
 void
 AudioOutput::Disable() noexcept
 {
-	const ScopeUnlock unlock(mutex);
 	ao_plugin_disable(*this);
 }
 

src/output/Thread.cxx

@@ -104,7 +104,11 @@ AudioOutputControl::InternalEnable() noexcept
 	last_error = nullptr;
 
 	try {
-		output->Enable();
+		{
+			const ScopeUnlock unlock(mutex);
+			output->Enable();
+		}
+
 		really_enabled = true;
 		return true;
 	} catch (const std::runtime_error &e) {
@@ -124,6 +128,8 @@ AudioOutputControl::InternalDisable() noexcept
 	InternalCheckClose(false);
 
 	really_enabled = false;
+
+	const ScopeUnlock unlock(mutex);
 	output->Disable();
 }