Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index fc44741..2c4dda0 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * acpi_processor.c - ACPI processor enumeration support
  *
@@ -7,10 +8,6 @@
  * Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
  * Copyright (C) 2013, Intel Corporation
  *                     Rafael J. Wysocki <rafael.j.wysocki@intel.com>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published
- * by the Free Software Foundation.
  */
 
 #include <linux/acpi.h>
@@ -282,9 +279,13 @@
 	}
 
 	if (acpi_duplicate_processor_id(pr->acpi_id)) {
-		dev_err(&device->dev,
-			"Failed to get unique processor _UID (0x%x)\n",
-			pr->acpi_id);
+		if (pr->acpi_id == 0xff)
+			dev_info_once(&device->dev,
+				"Entry not well-defined, consider updating BIOS\n");
+		else
+			dev_err(&device->dev,
+				"Failed to get unique processor _UID (0x%x)\n",
+				pr->acpi_id);
 		return -ENODEV;
 	}