Kernel: Add support for Intel HDA

This is an implementation that tries to follow the spec as closely as
possible, and works with Qemu's Intel HDA and some bare metal HDA
controllers out there. Compiling with `INTEL_HDA_DEBUG=on` will provide
a lot of detailed information that could help us getting this to work
on more bare metal controllers as well :^)

Output format is limited to `i16` samples for now.

Kernel/Devices/Audio/IntelHDA/Format.h

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2023, Jelle Raaijmakers <jelle@gmta.nl>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Error.h>
+#include <AK/Types.h>
+
+namespace Kernel::Audio::IntelHDA {
+
+struct FormatParameters {
+    u32 sample_rate;
+    u8 pcm_bits;
+    u8 number_of_channels;
+};
+
+ErrorOr<u16> encode_format(FormatParameters format);
+ErrorOr<FormatParameters> decode_format(u16 format);
+
+}