bmc: add update mechanism interface

Add mechanism definition for an update interface.  Does not provide an
implementation.

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: I8d8f04538524ab42de19843844fef3eec6bbd140
diff --git a/status.hpp b/status.hpp
index c5ea42a..667c050 100644
--- a/status.hpp
+++ b/status.hpp
@@ -12,4 +12,14 @@
     failed = 2,
     other = 3,
 };
-}
+
+/** The status of the update mechanism. */
+enum class UpdateStatus : std::uint8_t
+{
+    running = 0,
+    success = 1,
+    failed = 2,
+    unknown = 3,
+};
+
+} // namespace ipmi_flash