s390/pci: add zpci_report_error interface

The 'report_error' interface for PCI devices found on s390 can be
used by a user space program to inject an adapter error notification.
Add a new kernel interface zpci_report_error to allow a PCI device
driver to inject these error notifications without a detour over
user space.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>