s390/qdio: don't release memory in qdio_setup_irq()

Calling qdio_release_memory() on error is just plain wrong. It frees
the main qdio_irq struct, when following code still uses it.

Also, no other error path in qdio_establish() does this. So trust
callers to clean up via qdio_free() if some step of the QDIO
initialization fails.

Fixes: 779e6e1c

 ("[S390] qdio: new qdio driver.")
Cc: <stable@vger.kernel.org> #v2.6.27+
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>