s390/qdio: cleanup chsc SSQD usage

Cleanup the function qdio_setup_get_ssqd. Fix some possible
memleaks and an unchecked allocation and create a wrapper
for SSQD in chsc.c .

Reviewed-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>