linux-phytec-ti

s390/dasd: fix read unit address configuration loop

Read unit address is done for all devices during online processing to read
out LCU features. This is also done after disconnect/connect a LCU.
Some older storage hardware does not provide the capability to read unit
address configuration.
This leads to a loop trying to read unit address configuration every 30
seconds. The device is still operational but logs are flooded with error
messages.

Fix the loop by recognizing a command reject saying that the suborder
for ruac is not supported.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>