powerpc/perf: Fix pmu_count to count only nest imc pmus

"pmu_count" in opal_imc_counters_probe() is intended to hold
the number of successful nest imc pmu registerations. But
current code also counts other imc units like core_imc and
thread_imc. Patch add a check to count only nest imc pmus.
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/powernv/opal-imc.c

@@ -191,8 +191,10 @@ static int opal_imc_counters_probe(struct platform_device *pdev)
 			break;
 		}
 
-		if (!imc_pmu_create(imc_dev, pmu_count, domain))
-			pmu_count++;
+		if (!imc_pmu_create(imc_dev, pmu_count, domain)) {
+			if (domain == IMC_DOMAIN_NEST)
+				pmu_count++;
+		}
 	}
 
 	return 0;