coresight: etm4x: core: Remove redundant check of attr

"attr" is checked by perf framework, so remove the redundant check in
etm4_parse_event_config().

Link: https://lore.kernel.org/r/1620912469-52222-4-git-send-email-liuqi115@huawei.com
Signed-off-by: Junhao He <hejunhao2@hisilicon.com>
Signed-off-by: Qi Liu <liuqi115@huawei.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20210614175901.532683-5-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hwtracing/coresight/coresight-etm4x-core.c

@@ -568,11 +568,6 @@ static int etm4_parse_event_config(struct etmv4_drvdata *drvdata,
 	struct etmv4_config *config = &drvdata->config;
 	struct perf_event_attr *attr = &event->attr;
 
-	if (!attr) {
-		ret = -EINVAL;
-		goto out;
-	}
-
 	/* Clear configuration from previous run */
 	memset(config, 0, sizeof(struct etmv4_config));