staging: olpc_dcon: prefer 'help' in KConfig

Fix for a style warning reported by checkpatch.pl in KConfig
suggesting to use 'help' instead of '---help---'.

Signed-off-by: Cristian Kubis <cristian.kubis@tsunix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>