[S390] Remove Kerntypes leftovers

Remove last traces of our kerntypes patch which was always an addon
patch which never got upstream. Somehow a few bits got upstream
anyway.
Since kerntypes aren't used anymore and lcrash isn't maintained (for
s390 at least) remove the last traces of kerntypes that somehow went
upstream. Also remove the documentation that mentions lcrash.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>