qdio_establish() calls qdio_setup_thinint() via qdio_setup_irq().
If the subsequent qdio_establish_thinint() fails, we miss to put the
DSCI again. Thus the DSCI isn't available for re-use. Given enough of
such errors, we could end up with having only the shared DSCI available.

Merge qdio_setup_thinint() into qdio_establish_thinint(), and deal with
such an error internally.

Fixes: 779e6e1c ("[S390] qdio: new qdio driver.")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>