qeth: allow qdio queue element addresses > 2GB

OSA-adapters do not have an address limitation for the qdio queue
structures except the MAX storage level of the current processor.
And due to a recent z/VM APAR there is no longer a restriction to
allocate qdio structures below 2 GB.

Signed-off-by: Ursula Braun <braunu@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>