[wip] Add dummy cache module

Needs CLIDR_EL1 implementantion in cortex-a first

nucleus/src/arch/aarch64/memory/cache.rs

@@ -0,0 +1,3 @@
+/*
+ * SPDX-License-Identifier: BlueOak-1.0.0
+ */

nucleus/src/arch/aarch64/memory/mod.rs

@@ -11,6 +11,7 @@ use {
 };
 
 mod addr;
+mod cache;
 pub mod mmu;
 
 pub use addr::PhysAddr;