Kernel/riscv64: Make the kernel compile

This commits inserts TODOs into all necessary places to make the kernel
compile on riscv64!

Kernel/Arch/riscv64/Interrupts.cpp

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2023, Sönke Holz <sholz8530@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/Error.h>
+#include <AK/Types.h>
+
+#include <Kernel/Arch/TrapFrame.h>
+#include <Kernel/Interrupts/GenericInterruptHandler.h>
+
+namespace Kernel {
+
+void dump_registers(RegisterState const&)
+{
+}
+
+// FIXME: Share the code below with Arch/x86_64/Interrupts.cpp
+//        While refactoring, the interrupt handlers can also be moved into the InterruptManagement class.
+GenericInterruptHandler& get_interrupt_handler(u8)
+{
+    TODO_RISCV64();
+}
+
+// Sets the reserved flag on `number_of_irqs` if it finds unused interrupt handler on
+// a contiguous range.
+ErrorOr<u8> reserve_interrupt_handlers(u8)
+{
+    TODO_RISCV64();
+}
+
+void register_generic_interrupt_handler(u8, GenericInterruptHandler&)
+{
+    TODO_RISCV64();
+}
+
+void unregister_generic_interrupt_handler(u8, GenericInterruptHandler&)
+{
+}
+
+void initialize_interrupts()
+{
+    TODO_RISCV64();
+}
+
+}