Revert "global: Remove CONFIG_SYS_EXTRA_OPTIONS support"

Unfortunately, we require additional logic to buildman to support this
removal and still use SYS_SOC, etc, for build targets.

This reverts commit eeec00072d7a0b5b91896d014618e558ce438738.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/boot/Kconfig b/boot/Kconfig
index 0514d3b..394b26f 100644
--- a/boot/Kconfig
+++ b/boot/Kconfig
@@ -339,6 +339,19 @@
 	  incorrect when used with device tree as this option does not
 	  exist / should not be used.
 
+config SYS_EXTRA_OPTIONS
+	string "Extra Options (DEPRECATED)"
+	help
+	  The old configuration infrastructure (= mkconfig + boards.cfg)
+	  provided the extra options field. If you have something like
+	  "HAS_BAR,BAZ=64", the optional options
+	    #define CONFIG_HAS
+	    #define CONFIG_BAZ	64
+	  will be defined in include/config.h.
+	  This option was prepared for the smooth migration from the old
+	  configuration to Kconfig. Since this option will be removed sometime,
+	  new boards should not use this option.
+
 config HAVE_SYS_TEXT_BASE
 	bool
 	depends on !NIOS2 && !XTENSA