Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/asm-generic/pgtable-nop4d.h b/include/asm-generic/pgtable-nop4d.h
index 04cb913..aebab90 100644
--- a/include/asm-generic/pgtable-nop4d.h
+++ b/include/asm-generic/pgtable-nop4d.h
@@ -26,6 +26,7 @@
 #define p4d_ERROR(p4d)				(pgd_ERROR((p4d).pgd))
 
 #define pgd_populate(mm, pgd, p4d)		do { } while (0)
+#define pgd_populate_safe(mm, pgd, p4d)		do { } while (0)
 /*
  * (p4ds are folded into pgds so this doesn't get actually called,
  * but the define is needed for a generic inline function.)