s390/qdio: remove unused support for SLIB parameters

Neither of the two drivers provides any SLIB parameter data, so get rid
of the dead code.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>