Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/of_net.h b/include/linux/of_net.h
index 90d81ee..6aeaea1 100644
--- a/include/linux/of_net.h
+++ b/include/linux/of_net.h
@@ -1,7 +1,6 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * OF helpers for network devices.
- *
- * This file is released under the GPLv2
  */
 
 #ifndef __LINUX_OF_NET_H
@@ -13,7 +12,6 @@
 struct net_device;
 extern int of_get_phy_mode(struct device_node *np);
 extern const void *of_get_mac_address(struct device_node *np);
-extern int of_get_nvmem_mac_address(struct device_node *np, void *addr);
 extern struct net_device *of_find_net_device_by_node(struct device_node *np);
 #else
 static inline int of_get_phy_mode(struct device_node *np)
@@ -23,12 +21,7 @@
 
 static inline const void *of_get_mac_address(struct device_node *np)
 {
-	return NULL;
-}
-
-static inline int of_get_nvmem_mac_address(struct device_node *np, void *addr)
-{
-	return -ENODEV;
+	return ERR_PTR(-ENODEV);
 }
 
 static inline struct net_device *of_find_net_device_by_node(struct device_node *np)