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/README.kconfig b/doc/README.kconfig
index 0689f66..808cf56 100644
--- a/doc/README.kconfig
+++ b/doc/README.kconfig
@@ -99,7 +99,6 @@
  Vendor      ->  CONFIG_SYS_VENDOR defined by Kconfig
  Board       ->  CONFIG_SYS_BOARD defined by Kconfig
  Target      ->  File name of defconfig (configs/<target>_defconfig)
- Options     ->  CONFIG_SYS_EXTRA_OPTIONS defined by Kconfig
  Maintainers ->  "M:" entry of MAINTAINERS
 
 
@@ -140,12 +139,6 @@
 TODO
 ----
 
-- The option field of boards.cfg, which was used for the pre-Kconfig
-  configuration, moved to CONFIG_SYS_EXTRA_OPTIONS verbatim now.
-  Board maintainers are expected to implement proper Kconfig options
-  and switch over to them.  Eventually CONFIG_SYS_EXTRA_OPTIONS will go away.
-  CONFIG_SYS_EXTRA_OPTIONS should not be used for new boards.
-
 - In the pre-Kconfig, a single board had multiple entries in the boards.cfg
   file with differences in the option fields.  The corresponding defconfig
   files were auto-generated when switching to Kconfig.  Now we have too many
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::