sh64: deprecate support for this dead architecture

As discussed on the mailinglist, this should be deprecated
before removal.

[Thomas: don't add to Config.in.legacy.]

Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

arch/Config.in

@@ -163,6 +163,7 @@ config BR2_sh
 
 config BR2_sh64
 	bool "SuperH64"
+	depends on BR2_DEPRECATED_SINCE_2015_05
 	help
 	  SuperH64 (or SH) is a 64-bit reduced instruction set computer (RISC)
 	  instruction set architecture (ISA) developed by Hitachi.