Revert "Revert "global: Remove CONFIG_SYS_EXTRA_OPTIONS support""

This is not needed now that CONFIG_SYS_TARGET_NAME is correctly determined
when scanning Kconfig.

This reverts commit 25b8acee2ea11a9edc100c42a61f5d6187eb6167.

Signed-off-by: Simon Glass <sjg@chromium.org>
Suggested-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/doc/develop/moveconfig.rst b/doc/develop/moveconfig.rst
index 2f53ea5..bfb7aff 100644
--- a/doc/develop/moveconfig.rst
+++ b/doc/develop/moveconfig.rst
@@ -295,8 +295,7 @@
 
  -y, --yes
    Instead of prompting, automatically go ahead with all operations. This
-   includes cleaning up headers, CONFIG_SYS_EXTRA_OPTIONS, the config whitelist
-   and the README.
+   includes cleaning up headers, the config whitelist and the README.
 
 To see the complete list of supported options, run::