Update clang-tidy

Fix a bunch of minor issues, ignore others.  We use a lot of global
variables.  Enabling a check will hopefully make sure we don't add more.

Change-Id: Ie76053d4afc95a5372b70b2fb768be464468cec0
Signed-off-by: Ed Tanous <ed@tanous.net>
diff --git a/src/fru_utils.cpp b/src/fru_utils.cpp
index e18d55b..6e6ba84 100644
--- a/src/fru_utils.cpp
+++ b/src/fru_utils.cpp
@@ -191,6 +191,11 @@
             }
         }
         break;
+
+        default:
+        {
+            return make_pair(DecodeState::err, value);
+        }
     }
 
     return make_pair(DecodeState::ok, value);