qeth: do not apply priority queuing to HiperSockets

OSA cards can be configured to support 1 or 4 output queues. This
does not apply to HiperSockets. This patch limits determination of
the configured number of output queues to OSA cards only, but excludes
HiperSockets.

Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>