Kernel: Decouple Intel HDA interrupt handling from controller

The driver would crash if it was unable to find an output route, and
subsequently the destruction of controller did not invoke
`GenericInterruptHandler::will_be_destroyed()` because on the level of
`AudioController`, that method is unavailable.

By decoupling the interrupt handling from the controller, we get a new
refcounted class that correctly cleans up after itself :^)

Kernel/Devices/Audio/IntelHDA/InterruptHandler.h

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2023, Jelle Raaijmakers <jelle@gmta.nl>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/NonnullRefPtr.h>
+#include <Kernel/Interrupts/PCIIRQHandler.h>
+
+namespace Kernel::Audio::IntelHDA {
+
+class Controller;
+
+class InterruptHandler
+    : public PCIIRQHandler
+    , public RefCounted<InterruptHandler> {
+public:
+    static ErrorOr<NonnullRefPtr<InterruptHandler>> create(Controller& controller)
+    {
+        return adopt_nonnull_ref_or_enomem(new (nothrow) InterruptHandler(controller));
+    }
+
+    // ^PCIIRQHandler
+    virtual StringView purpose() const override { return "IntelHDA IRQ Handler"sv; }
+
+private:
+    InterruptHandler(Controller& controller);
+
+    // ^PCIIRQHandler
+    virtual bool handle_irq(RegisterState const&) override;
+
+    Controller& m_controller;
+};
+
+}