Kernel: Move all Graphics-related code into Devices/GPU directory

Like the HID, Audio and Storage subsystem, the Graphics subsystem (which
handles GPUs technically) exposes unix device files (typically in /dev).
To ensure consistency across the repository, move all related files to a
new directory under Kernel/Devices called "GPU".

Also remove the redundant "GPU" word from the VirtIO driver directory,
and the word "Graphics" from GraphicsManagement.{h,cpp} filenames.

Kernel/Devices/GPU/Intel/Auxiliary/GMBusConnector.h

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2022, Liav A. <liavalb@hotmail.co.il>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/RefPtr.h>
+#include <AK/Try.h>
+#include <AK/Types.h>
+#include <Kernel/Locking/Spinlock.h>
+#include <Kernel/Memory/TypedMapping.h>
+
+namespace Kernel {
+
+struct [[gnu::packed]] GMBusRegisters {
+    u32 clock;
+    u32 command;
+    u32 status;
+    u32 data;
+};
+
+enum class GMBusStatus;
+
+class GMBusConnector {
+public:
+    enum PinPair : u8 {
+        None = 0,
+        DedicatedControl = 1,
+        DedicatedAnalog = 0b10,
+        IntegratedDigital = 0b11,
+        sDVO = 0b101,
+        Dconnector = 0b111,
+    };
+
+public:
+    static ErrorOr<NonnullOwnPtr<GMBusConnector>> create_with_physical_address(PhysicalAddress gmbus_start_address);
+
+    ErrorOr<void> write(unsigned address, u32 data);
+    ErrorOr<void> read(unsigned address, u8* buf, size_t length);
+    void set_default_rate();
+
+private:
+    void set_pin_pair(PinPair pin_pair);
+
+    bool wait_for(GMBusStatus desired_status, size_t milliseconds_timeout);
+
+    explicit GMBusConnector(Memory::TypedMapping<GMBusRegisters volatile>);
+    Spinlock<LockRank::None> m_access_lock;
+    Memory::TypedMapping<GMBusRegisters volatile> m_gmbus_registers;
+};
+}