This replaces all usages of Cacheable::Yes with MemoryType::Normal and
Cacheable::No with either MemoryType::NonCacheable or MemoryType::IO,
depending on the context.
The Page{Directory,Table}::set_cache_disabled function therefore also
has been replaced with a more appropriate set_memory_type_function.
Adding a memory_type "getter" would not be as easy, as some
architectures may not support all memory types, so getting the memory
type again may be a lossy conversion. The is_cache_disabled function
was never used, so just simply remove it altogether.
There is no difference between MemoryType::NonCacheable and
MemoryType::IO on x86 for now.
Other architectures currently don't respect the MemoryType at all.
We don't really need it, and the entire functionality can be organically
intergrated into the VirtualConsole class, to switch between the Virtual
consoles, and manage initialization of all consoles in the global array.
As MMIO is placed at fixed physical addressed, and does not need to be
backed by real RAM physical pages, there's no need to use PhysicalPage
instances to track their pages.
This results in slightly reduced allocations, but more importantly
makes MMIO addresses which end up after the normal RAM ranges work,
like 64-bit PCI BARs usually are.
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.
