Config.in: Add BR2_DEPRECATED_SINCE_2015_05

In preparation for the deprecation of certain features in 2015.05, add
the BR2_DEPRECATED_SINCE_2015_05 symbol.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Config.in

@@ -312,6 +312,10 @@ config BR2_DEPRECATED_SINCE_2015_02
 	bool
 	default y
 
+config BR2_DEPRECATED_SINCE_2015_05
+	bool
+	default y
+
 endif
 
 config BR2_ENABLE_DEBUG