s390/qeth: unify structs for bridge port state

The data returned from IPA_SBP_QUERY_BRIDGE_PORTS and
IPA_SBP_BRIDGE_PORT_STATE_CHANGE has the same format. Use a single
struct definition for it.

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