Query AP configuration information. Improve performance of AP bus
scans by skipping AP device probing, if the AP deviec is not
configured.
Reviewed-by: NIngo Tuchscherer <ingo.tuchscherer@linux.vnet.ibm.com>
Signed-off-by: NHolger Dengler <hd@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>