s390/ism: move oddities of device IO to wrapper function

ISM devices are special in how they access PCI memory space. Provide
wrappers for handling commands to the device. No functional change.

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