[S390] dasd: check_characteristics cleanup

Fix a broken memset (sizeof pointer vs sizeof the underlying
structure) by cleaning up the involved functions.

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

diff --cc drivers/s390/block/dasd.c
Simple merge

diff --cc drivers/s390/block/dasd_eckd.c
Simple merge

diff --cc drivers/s390/block/dasd_fba.c
Simple merge

diff --cc drivers/s390/block/dasd_int.h
Simple merge