vmbase: Move hvc to aarch64

This commit move ARM hypercall interface to aarch64 directories.

Bug: 362733888
Test: m libvmbase

Change-Id: I17666437670feb9528c6871a36f9d6ecd3ea95d4
diff --git a/libs/libvmbase/src/rand.rs b/libs/libvmbase/src/rand.rs
index 16c7b6a..e4623b7 100644
--- a/libs/libvmbase/src/rand.rs
+++ b/libs/libvmbase/src/rand.rs
@@ -14,7 +14,7 @@
 
 //! Functions and drivers for obtaining true entropy.
 
-use crate::hvc;
+use crate::arch::aarch64::hvc;
 use core::fmt;
 use core::mem::size_of;
 use smccc::{self, Hvc};