[Coverity] Fix some null checks

renderdocui/Code/Cameras.cs

@@ -55,8 +55,6 @@ namespace renderdocui.Code
 
             var me = (TimedUpdate)state;
 
-            if (me == null) return;
-
             if (me.m_Update != null) me.m_Update();
             if (me.m_CameraTick != null) me.m_CameraTick.Change(me.m_Rate, System.Threading.Timeout.Infinite);
         }

renderdocui/Interop/ReplayRenderer.cs

@@ -1233,6 +1233,9 @@ namespace renderdoc
                     CustomMarshal.Free(mem);
                 }
 
+                if (msg == null)
+                    return;
+
                 if (msg.Type == TargetControlMessageType.Disconnected)
                 {
                     m_Connected = false;