Kernel: Rewrite whole device structure

We now have DevFileSystem which is derived from RamFileSystem. All
devices are RamInodes. We don't have separate DeviceManager anymore.
To iterate over devices, you can loop througn every inode in devfs.

kernel/include/kernel/PCI.h

@@ -60,6 +60,7 @@ namespace Kernel
 		void check_device(uint8_t bus, uint8_t dev);
 		void check_bus(uint8_t bus);
 		void check_all_buses();
+		void initialize_devices();
 
 	private:
 		BAN::Vector<PCIDevice> m_devices;