tools/handler: Read the running version

A host tool would read the running firmware version through polling the
version blob state.

Signed-off-by: Jie Yang <jjy@google.com>
Change-Id: I0d68fff6527cd52360abee1cb225a8f228d68392
diff --git a/util.hpp b/util.hpp
index 8e579f5..3deebb4 100644
--- a/util.hpp
+++ b/util.hpp
@@ -13,6 +13,7 @@
 inline constexpr char staticLayoutBlobId[] = "/flash/image";
 inline constexpr char ubiTarballBlobId[] = "/flash/tarball";
 inline constexpr char cleanupBlobId[] = "/flash/cleanup";
+inline constexpr char biosVersionBlobId[] = "/version/bios";
 
 /** @brief Lightweight class wrapper that removes move operations from a class
  *         in order to guarantee the contents stay pinned to a specific location