powerpc/perf/hv-24x7: Support v2 of the hypervisor API

POWER9 introduces a new version of the hypervisor API to access the 24x7
perf counters. The new version changed some of the structures used for
requests and results.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>