drm/i915/pmu: Fix uninitialized variable on error path

If name allocation failed the log message will contain an uninitialized
error code which can be confusing.

Fixes: 05488673 ("drm/i915/pmu: Support multiple GPUs")
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191018090514.1818-1-tvrtko.ursulin@linux.intel.com
[tursulin: Commit message spelling fix.]

drivers/gpu/drm/i915/i915_pmu.c

@@ -1094,7 +1094,7 @@ static bool is_igp(struct drm_i915_private *i915)
 void i915_pmu_register(struct drm_i915_private *i915)
 {
 	struct i915_pmu *pmu = &i915->pmu;
-	int ret;
+	int ret = -ENOMEM;
 
 	if (INTEL_GEN(i915) <= 2) {
 		dev_info(i915->drm.dev, "PMU not supported for this GPU.");
@@ -1102,10 +1102,8 @@ void i915_pmu_register(struct drm_i915_private *i915)
 	}
 
 	i915_pmu_events_attr_group.attrs = create_event_attributes(pmu);
-	if (!i915_pmu_events_attr_group.attrs) {
-		ret = -ENOMEM;
+	if (!i915_pmu_events_attr_group.attrs)
 		goto err;
-	}
 
 	pmu->base.attr_groups	= i915_pmu_attr_groups;
 	pmu->base.task_ctx_nr	= perf_invalid_context;