Kernel: Make FIFO inherit from File.

Kernel/Devices/Device.cpp

@@ -1,4 +1,5 @@
-#include "CharacterDevice.h"
+#include <Kernel/Devices/Device.h>
+#include <Kernel/FileSystem/VirtualFileSystem.h>
 #include <LibC/errno_numbers.h>
 
 Device::Device(unsigned major, unsigned minor)

Kernel/Devices/Device.h

@@ -34,6 +34,7 @@
 //
 
 #include <Kernel/File.h>
+#include <Kernel/UnixTypes.h>
 
 class Device : public File {
 public:

Kernel/Devices/PS2MouseDevice.h

@@ -3,6 +3,7 @@
 #include <Kernel/Devices/CharacterDevice.h>
 #include <Kernel/MousePacket.h>
 #include <Kernel/IRQHandler.h>
+#include <AK/CircularQueue.h>
 
 class PS2MouseDevice final : public IRQHandler, public CharacterDevice {
 public: