s390/dasd: retry partition detection
s390/dasd: retry partition detection

In case somebody attempted to open the device during online
processing the partition detection ioctl may have failed.

Added a retry loop to avoid not detected partitions.

Signed-off-by: Stefan Haberland <9e6a0bb809a7918e8f27f36fc1281e79ae9e5bd0@de.ibm.com>
Signed-off-by: Martin Schwidefsky <52616596d8f5df0d597e85ab515377f92f939c68@de.ibm.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs