clang-format: Update to match docs repo

Update the .clang-format file and run clang-format-6.0.
This .clang-format matches the example one in
https://github.com/openbmc/docs/blob/master/cpp-style-and-conventions.md#clang-formatting

Change-Id: Ic2c462525eb27b8295c2b298871e04268d93faf2
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/property_change_listener.hpp b/property_change_listener.hpp
index de23f47..a19a228 100644
--- a/property_change_listener.hpp
+++ b/property_change_listener.hpp
@@ -9,15 +9,17 @@
 
 class PropertyChangeListner
 {
-    public:
-        virtual ~PropertyChangeListner() {}
+  public:
+    virtual ~PropertyChangeListner()
+    {
+    }
 
-        /** @brief Notified on time mode is changed */
-        virtual void onModeChanged(Mode mode) = 0;
+    /** @brief Notified on time mode is changed */
+    virtual void onModeChanged(Mode mode) = 0;
 
-        /** @brief Notified on time owner is changed */
-        virtual void onOwnerChanged(Owner owner) = 0;
+    /** @brief Notified on time owner is changed */
+    virtual void onOwnerChanged(Owner owner) = 0;
 };
 
-}
-}
+} // namespace time
+} // namespace phosphor