arm_pmu: Remove unused PERF_PMU_CAP_HETEROGENEOUS_CPUS capability

Since commit bd27568 ("perf: Rewrite core context handling") the
relationship between perf_event_context and PMUs has changed so that
the error scenario that PERF_PMU_CAP_HETEROGENEOUS_CPUS originally
silenced no longer exists.

Remove the capability and associated comment to avoid confusion that it
actually influences any perf core behavior. This change should be a
no-op.

Signed-off-by: James Clark <james.clark@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20230724134500.970496-4-james.clark@arm.com

Author: James-A-Clark

drivers/perf/arm_pmu.c

@@ -877,15 +877,12 @@ struct arm_pmu *armpmu_alloc(void)
 		.attr_groups	= pmu->attr_groups,
 		/*
 		 * This is a CPU PMU potentially in a heterogeneous
-		 * configuration (e.g. big.LITTLE). This is not an uncore PMU,
-		 * and we have taken ctx sharing into account (e.g. with our
-		 * pmu::filter callback and pmu::event_init group validation).
-		 *
+		 * configuration (e.g. big.LITTLE) so
 		 * PERF_PMU_CAP_EXTENDED_HW_TYPE is required to open
 		 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE events on a
 		 * specific PMU.
 		 */
-		.capabilities	= PERF_PMU_CAP_HETEROGENEOUS_CPUS | PERF_PMU_CAP_EXTENDED_REGS |
+		.capabilities	= PERF_PMU_CAP_EXTENDED_REGS |
 				  PERF_PMU_CAP_EXTENDED_HW_TYPE,
 	};