drm/i915/pmu: Remove conditional HOTPLUG_CPU registration

Even for static CPU configurations, the hotplug CPU framework is still
used to determine the CPU topology, and is still being used by the perf
event register to check for valid CPUs.

Fixes: b46a33e271ed ("drm/i915/pmu: Expose a PMU interface for perf queries")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Dmitry Rogozhkin <dmitry.v.rogozhkin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171123123432.25035-1-tvrtko.ursulin@linux.intel.com

drivers/gpu/drm/i915/i915_pmu.c

@@ -40,7 +40,7 @@
 
 #define ENGINE_SAMPLE_BITS (1 << I915_PMU_SAMPLE_BITS)
 
-static cpumask_t i915_pmu_cpumask = CPU_MASK_NONE;
+static cpumask_t i915_pmu_cpumask;
 
 static u8 engine_config_sample(u64 config)
 {
@@ -770,7 +770,6 @@ static const struct attribute_group *i915_pmu_attr_groups[] = {
 	NULL
 };
 
-#ifdef CONFIG_HOTPLUG_CPU
 static int i915_pmu_cpu_online(unsigned int cpu, struct hlist_node *node)
 {
 	struct i915_pmu *pmu = hlist_entry_safe(node, typeof(*pmu), node);
@@ -806,11 +805,9 @@ static int i915_pmu_cpu_offline(unsigned int cpu, struct hlist_node *node)
 }
 
 static enum cpuhp_state cpuhp_slot = CPUHP_INVALID;
-#endif
 
 static int i915_pmu_register_cpuhp_state(struct drm_i915_private *i915)
 {
-#ifdef CONFIG_HOTPLUG_CPU
 	enum cpuhp_state slot;
 	int ret;
 
@@ -829,17 +826,14 @@ static int i915_pmu_register_cpuhp_state(struct drm_i915_private *i915)
 	}
 
 	cpuhp_slot = slot;
-#endif
 	return 0;
 }
 
 static void i915_pmu_unregister_cpuhp_state(struct drm_i915_private *i915)
 {
-#ifdef CONFIG_HOTPLUG_CPU
 	WARN_ON(cpuhp_slot == CPUHP_INVALID);
 	WARN_ON(cpuhp_state_remove_instance(cpuhp_slot, &i915->pmu.node));
 	cpuhp_remove_multi_state(cpuhp_slot);
-#endif
 }
 
 void i915_pmu_register(struct drm_i915_private *i915)