s390/pci: add ioctl interface for CLP

s390/pci: add ioctl interface for CLP

BugLink: http://bugs.launchpad.net/bugs/1558624
Provide a user space interface to issue call logical-processor instructions.
Only selected CLP commands are allowed, enough to get the full overview of
the installed PCI functions.

Reviewed-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
(cherry picked from commit 988b86e69ded17f0f1209fd3ef1c4c7f1567dcc1)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>