vmbase: Move Trng internals to arch::aarch64

This commit moves trng implementation from common rand module to a
aarch64 arch module. This is at the moment purely cosmetic change,
however the purpose is move all aarch64 specific code away from common
modules to enable bringup of x86_64 support.

Bug: 362733888
Test: m pvmfw
Test: pVM boots with pvmfw
Change-Id: I5ac315ed38491de8b66f07a5df703cb50786c8bb
diff --git a/libs/libvmbase/src/arch.rs b/libs/libvmbase/src/arch.rs
index 49978d5..cc42939 100644
--- a/libs/libvmbase/src/arch.rs
+++ b/libs/libvmbase/src/arch.rs
@@ -30,6 +30,9 @@
 pub use aarch64::dbm;
 
 #[cfg(target_arch = "aarch64")]
+pub use aarch64::rand;
+
+#[cfg(target_arch = "aarch64")]
 pub use aarch64::uart;
 
 #[cfg(target_arch = "aarch64")]