Kernel: Much improved BochsVGA (BXVGA) support.

Instead of cowboy-calling the VESA BIOS in the bootloader, find the emulator
VGA adapter by scanning the PCI bus. Then set up the desired video mode by
sending device commands.

Kernel/BochsVGADevice.h

@@ -0,0 +1,25 @@
+#pragma once
+
+#include <AK/Types.h>
+#include <AK/AKString.h>
+#include <Kernel/types.h>
+
+// FIXME: This should be a BlockDevice once we have BlockDevice.
+
+class BochsVGADevice {
+    AK_MAKE_ETERNAL
+public:
+    static BochsVGADevice& the();
+    static void initialize_statics();
+
+    BochsVGADevice();
+
+    PhysicalAddress framebuffer_address() const { return m_framebuffer_address; }
+    void set_resolution(int width, int height);
+
+private:
+    void set_register(word index, word value);
+    dword find_framebuffer_address();
+
+    PhysicalAddress m_framebuffer_address;
+};