Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/debug_locks.h b/include/linux/debug_locks.h
index 120225e..257ab3c 100644
--- a/include/linux/debug_locks.h
+++ b/include/linux/debug_locks.h
@@ -8,8 +8,8 @@
 
 struct task_struct;
 
-extern int debug_locks;
-extern int debug_locks_silent;
+extern int debug_locks __read_mostly;
+extern int debug_locks_silent __read_mostly;
 
 
 static inline int __debug_locks_off(void)