powerpc/pseries: Add new hvcall constants to support PFO

The Platform Facilities Option (PFO) adds several new h_calls and
more return codes.

Signed-off-by: Robert Jennings <rcj@linux.vnet.ibm.com>
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>