perf: Add PMU_FORMAT_ATTR_SHOW

The macro PMU_FORMAT_ATTR facilitates the definition of both the "show"
function and "format_attr". But it only works for a non-hybrid platform.
For a hybrid platform, the name "format_attr_hybrid_" is used.

The definition of the "show" function can be shared between a non-hybrid
platform and a hybrid platform. Add a new macro PMU_FORMAT_ATTR_SHOW.

No functional change. The PMU_FORMAT_ATTR_SHOW will be used in the
following patch.
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230104201349.1451191-1-kan.liang@linux.intel.com

include/linux/perf_event.h

@@ -1724,7 +1724,7 @@ static struct perf_pmu_events_attr _var = {				    \
 		  .id = _id, }						\
 	})[0].attr.attr)
 
-#define PMU_FORMAT_ATTR(_name, _format)					\
+#define PMU_FORMAT_ATTR_SHOW(_name, _format)				\
 static ssize_t								\
 _name##_show(struct device *dev,					\
 			       struct device_attribute *attr,		\
@@ -1733,6 +1733,9 @@ _name##_show(struct device *dev,					\
 	BUILD_BUG_ON(sizeof(_format) >= PAGE_SIZE);			\
 	return sprintf(page, _format "\n");				\
 }									\
+
+#define PMU_FORMAT_ATTR(_name, _format)					\
+	PMU_FORMAT_ATTR_SHOW(_name, _format)				\
 									\
 static struct device_attribute format_attr_##_name = __ATTR_RO(_name)