linux-phytec-fsl

[S390] css: remove subchannel private

All subchannel drivers use drv_data, so get rid of the
additional private pointer of struct subchannel.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>