selftests/powerpc/pmu: Add selftest for PERF_TYPE_HARDWARE events valid check

Testcase to ensure that using invalid event in generic event for
PERF_TYPE_HARDWARE will fail. Invalid generic events in power10 are:
- PERF_COUNT_HW_BUS_CYCLES
- PERF_COUNT_HW_STALLED_CYCLES_FRONTEND
- PERF_COUNT_HW_STALLED_CYCLES_BACKEND
- PERF_COUNT_HW_REF_CPU_CYCLES

Invalid generic events in power9 are:
- PERF_COUNT_HW_BUS_CYCLES
- PERF_COUNT_HW_REF_CPU_CYCLES

Testcase does event open for valid and invalid generic events to ensure
event open works for all valid events and fails for invalid events.

Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220610134113.62991-29-atrajeev@linux.vnet.ibm.com