perf: Add EVENT_ATTR_ID to simplify event attributes

Similar EVENT_ATTR macros are defined in many PMU drivers,
like Arm PMU driver, Arm SMMU PMU driver. So add a generic
macro to simplify code.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Qi Liu <liuqi115@huawei.com>
Link: https://lore.kernel.org/r/1623220863-58233-2-git-send-email-liuqi115@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>

Author: 77liuqi

include/linux/perf_event.h

@@ -1576,6 +1576,12 @@ static struct perf_pmu_events_attr _var = {				    \
 	.event_str	= _str,						    \
 };
 
+#define PMU_EVENT_ATTR_ID(_name, _show, _id)				\
+	(&((struct perf_pmu_events_attr[]) {				\
+		{ .attr = __ATTR(_name, 0444, _show, NULL),		\
+		  .id = _id, }						\
+	})[0].attr.attr)
+
 #define PMU_FORMAT_ATTR(_name, _format)					\
 static ssize_t								\
 _name##_show(struct device *dev,					\