tools: add data interface type

Add data interface type to the object, to allow checking against what
stat() returns.

Change-Id: I72aed1ffbca63dbfb003359c4bbe570f966a8649
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/tools/updater.cpp b/tools/updater.cpp
index 7b5ec0f..a7f9c96 100644
--- a/tools/updater.cpp
+++ b/tools/updater.cpp
@@ -44,6 +44,11 @@
      * is supported.
      */
     auto stat = blob->getStat(goalFirmware);
+    if ((stat.blob_state & handler->supportedType()) == 0)
+    {
+        std::fprintf(stderr, "data interface selected not supported.\n");
+        return -1; /* throw custom exception. */
+    }
 
     return 0;
 }