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/Bochs/Definitions.h

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2022, Liav A. <liavalb@hotmail.co.il>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Types.h>
+
+namespace Kernel {
+
+#define VBE_DISPI_IOPORT_INDEX 0x01CE
+#define VBE_DISPI_IOPORT_DATA 0x01CF
+
+#define BOCHS_DISPLAY_LITTLE_ENDIAN 0x1e1e1e1e
+#define BOCHS_DISPLAY_BIG_ENDIAN 0xbebebebe
+
+#define VBE_DISPI_ID5 0xB0C5
+
+enum class BochsFramebufferSettings {
+    Enabled = 0x1,
+    LinearFramebuffer = 0x40,
+};
+
+enum class BochsDISPIRegisters {
+    ID = 0x0,
+    XRES = 0x1,
+    YRES = 0x2,
+    BPP = 0x3,
+    ENABLE = 0x4,
+    BANK = 0x5,
+    VIRT_WIDTH = 0x6,
+    VIRT_HEIGHT = 0x7,
+    X_OFFSET = 0x8,
+    Y_OFFSET = 0x9,
+    VIDEO_RAM_64K_CHUNKS_COUNT = 0xA,
+};
+
+struct [[gnu::packed]] DISPIInterface {
+    u16 index_id;
+    u16 xres;
+    u16 yres;
+    u16 bpp;
+    u16 enable;
+    u16 bank;
+    u16 virt_width;
+    u16 virt_height;
+    u16 x_offset;
+    u16 y_offset;
+    u16 vram_64k_chunks_count;
+};
+
+struct [[gnu::packed]] ExtensionRegisters {
+    u32 region_size;
+    u32 framebuffer_byteorder;
+};
+
+struct [[gnu::packed]] BochsDisplayMMIORegisters {
+    u8 edid_data[0x400];
+    u16 vga_ioports[0x10];
+    u8 reserved[0xE0];
+    DISPIInterface bochs_regs;
+    u8 reserved2[0x100 - sizeof(DISPIInterface)];
+    ExtensionRegisters extension_regs;
+};
+
+}