uboot: mark custom network settings as deprecated

As discussed on the the mailing list.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

Config.in

@@ -296,6 +296,10 @@ config BR2_DEPRECATED_SINCE_2014_02
 	bool
 	default y
 
+config BR2_DEPRECATED_SINCE_2014_05
+	bool
+	default y
+
 endif
 
 config BR2_ENABLE_DEBUG

boot/uboot/Config.in

@@ -169,6 +169,7 @@ endif
 
 menuconfig BR2_TARGET_UBOOT_NETWORK
 	bool "Custom Network Settings"
+	depends on BR2_DEPRECATED_SINCE_2014_05
 	help
 	  Custom network settings for U-boot