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 25b8acee.

Signed-off-by: Simon Glass <sjg@chromium.org>
Suggested-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Tom Rini <trini@konsulko.com>