[pvmfw][vmbase] Move MemoryTracker to vmbase for reuse

No behavior change in this cl.

Bug: 284462758
Test: m pvmfw_img
Change-Id: Id2970e3e8bb87d7c43903fe7e750b3c944178905
diff --git a/pvmfw/src/exceptions.rs b/pvmfw/src/exceptions.rs
index 4d376cd..c3f8a29 100644
--- a/pvmfw/src/exceptions.rs
+++ b/pvmfw/src/exceptions.rs
@@ -14,11 +14,10 @@
 
 //! Exception handlers.
 
-use crate::memory::MEMORY;
 use core::fmt;
 use vmbase::console;
 use vmbase::logger;
-use vmbase::memory::{page_4kb_of, MemoryTrackerError};
+use vmbase::memory::{page_4kb_of, MemoryTrackerError, MEMORY};
 use vmbase::read_sysreg;
 use vmbase::{eprintln, power::reboot};