zpcictl: Read device link to obtain device address
zpcictl: Read device link to obtain device address

The address sysfs attribute might not be present on some older kernel
levels. Read the device link instead using readlink() to obtain the
address.

Signed-off-by: Jan Höppner <96138615ab4af0813785fa10d283f3d37eca3b78@linux.ibm.com>

ibm-s390-tools/s390-tools,ibm-s390-tools/s390-tools,ibm-s390-tools/s390-tools,ibm-s390-tools/s390-tools