Kconfig: replace "--- help ---" with "---help---"

There are three Kconfig entries with "--- help ---" attributes, and over
2000 Kconfig entries with "---help---" attributes.  Apparently the three
attributes with embedded spaces are valid. Still, I see little reason
for using this obscure variant. And replacing those three attributes
with the common variant makes grepping Kconfig files for help texts a
bit easier too.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>