selftests/powerpc/pmu: Add selftest for group constraint check for MMCR0 l2l3_sel bits

In power10, L2L3 select bits in the event code is used to program
l2l3_sel field in Monitor Mode Control Register 0 (MMCR0: 56-60). When
scheduling events as a group, all events in that group should match
value in these bits. Otherwise event open for the sibling events will
fail.

Testcase uses event code "0x010000046080" as leader and another events
"0x26880" and "0x010000026880" as sibling events, and checks for
l2l3_sel constraints via perf interface for ISA v3.1 platform.

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220610134113.62991-30-atrajeev@linux.vnet.ibm.com