Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/tools/perf/util/mem-events.h b/tools/perf/util/mem-events.h
index a889ec2..f1389bd 100644
--- a/tools/perf/util/mem-events.h
+++ b/tools/perf/util/mem-events.h
@@ -6,6 +6,8 @@
 #include <stdint.h>
 #include <stdio.h>
 #include <linux/types.h>
+#include <linux/refcount.h>
+#include <linux/perf_event.h>
 #include "stat.h"
 
 struct perf_mem_event {
@@ -16,6 +18,13 @@
 	const char	*sysfs_name;
 };
 
+struct mem_info {
+	struct addr_map_symbol	iaddr;
+	struct addr_map_symbol	daddr;
+	union perf_mem_data_src	data_src;
+	refcount_t		refcnt;
+};
+
 enum {
 	PERF_MEM_EVENTS__LOAD,
 	PERF_MEM_EVENTS__STORE,