Config.in: Add BR2_DEPRECATED_SINCE_2016_05

In preparation for new deprecated features/symbols.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

Config.in

@@ -365,6 +365,10 @@ config BR2_DEPRECATED_SINCE_2016_02
 	bool
 	default y
 
+config BR2_DEPRECATED_SINCE_2016_05
+	bool
+	default y
+
 endif
 
 config BR2_ENABLE_DEBUG