powerpc/pseries: Pass CPPR value to H_XIRR hcall

Now that we properly keep track of the CPPR value (since
49bd3647134ea47420067aea8d1401e722bf2aac, "powerpc/pseries: Track previous
CPPR values to correctly EOI interrupts") we can pass it to the
H_XIRR hcall.

This is needed because the Partition Adjunct Option of new versions of
pHyp extend the H_XIRR hcall to include the CPPR as an input parameter.
Earlier versions not supporting this option just disregard the extra
input parameter, so this doesn't cause any problems for existing systems.

The Partition Adjunct Option is required for future systems that will
support SR-IOV capable devices.

Signed-off-by: Mark Nelson <markn@au1.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>