s390/qeth: get vnicc sub-cmd type from reply data

When processing the reply for a vnicc cmd, there's no need to remember
which specific sub-cmd type we initially sent. The reply itself contains
all the needed information.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>