Kernel: Don't use references or pointers to physical addresses

Now the ACPI & PCI code is more safer, because we don't use raw pointers
or references to objects or data that are located in the physical
address space, so an accidental dereference cannot happen easily.
Instead, we use the PhysicalAddress class to represent those addresses.

Kernel/PCI/Initializer.h

@@ -35,7 +35,7 @@ namespace Kernel {
 class PCI::Initializer {
 public:
     static PCI::Initializer& the();
-    void initialize_pci_mmio_access(ACPI_RAW::MCFG& mcfg);
+    void initialize_pci_mmio_access(PhysicalAddress mcfg);
     void initialize_pci_io_access();
     void test_and_initialize(bool disable_pci_mmio);
     static void dismiss();