[S390] cio: Remove deprecated rdc/rcd.

http://marc.info/?l=linux-kernel&m=118481061928246&w=2

 seems to
indicate disfavour of "deprecated", so let's just kill it now.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>