qeth: remove WARN_ON leftover

The patch "qeth: exploit asynchronous delivery of storage blocks"
added a WARN_ON in qeth_schedule_recovery. A device recovery should
not cause a kernel warning. This is obviously a debugging  left-over
that we forgot to remove.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>