s390/qdio: bridgeport support - CHSC part

Introduce function for the "Perform network-subchannel operation"
CHSC command with operation code "bridgeport information",
and bit definitions for "characteristics" pertaning to this command.

Signed-off-by: Eugene Crosser <eugene.crosser@ru.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Reviewed-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>