Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/kern_levels.h b/include/linux/kern_levels.h
index d237fe8..bf2389c 100644
--- a/include/linux/kern_levels.h
+++ b/include/linux/kern_levels.h
@@ -14,7 +14,7 @@
 #define KERN_INFO	KERN_SOH "6"	/* informational */
 #define KERN_DEBUG	KERN_SOH "7"	/* debug-level messages */
 
-#define KERN_DEFAULT	KERN_SOH "d"	/* the default kernel loglevel */
+#define KERN_DEFAULT	""		/* the default kernel loglevel */
 
 /*
  * Annotation for a "continued" line of log printout (only done after a