Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/asm-generic/pgtable-nop4d-hack.h b/include/asm-generic/pgtable-nop4d-hack.h
index 1d6dd38..829bdb0 100644
--- a/include/asm-generic/pgtable-nop4d-hack.h
+++ b/include/asm-generic/pgtable-nop4d-hack.h
@@ -31,6 +31,7 @@
 #define pud_ERROR(pud)				(pgd_ERROR((pud).pgd))
 
 #define pgd_populate(mm, pgd, pud)		do { } while (0)
+#define pgd_populate_safe(mm, pgd, pud)		do { } while (0)
 /*
  * (puds are folded into pgds so this doesn't get actually called,
  * but the define is needed for a generic inline function.)