[vmbase] Move RangeExt to vmbase for reuse

in both pvmfw and rialto.

No behavior change in this cl.

Bug: 284462758
Test: m pvmfw_img
Change-Id: Ifda7f4a2a08ebb6646c3c7e189a77c5ff3fe74a3
diff --git a/pvmfw/src/memory.rs b/pvmfw/src/memory.rs
index 30c11eb..216a621 100644
--- a/pvmfw/src/memory.rs
+++ b/pvmfw/src/memory.rs
@@ -16,7 +16,7 @@
 
 #![deny(unsafe_op_in_unsafe_fn)]
 
-use crate::helpers::{RangeExt, PVMFW_PAGE_SIZE};
+use crate::helpers::PVMFW_PAGE_SIZE;
 use aarch64_paging::idmap::IdMap;
 use aarch64_paging::paging::{Attributes, Descriptor, MemoryRegion as VaRange};
 use aarch64_paging::MapError;
@@ -44,7 +44,7 @@
         MMIO_LAZY_MAP_FLAG, SIZE_2MB, SIZE_4KB, SIZE_4MB,
     },
     tlbi,
-    util::align_up,
+    util::{align_up, RangeExt as _},
 };
 
 /// First address that can't be translated by a level 1 TTBR0_EL1.