Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/asm-generic/pgtable-nopud.h b/include/asm-generic/pgtable-nopud.h
index 9bef475..c77a1d3 100644
--- a/include/asm-generic/pgtable-nopud.h
+++ b/include/asm-generic/pgtable-nopud.h
@@ -35,6 +35,7 @@
 #define pud_ERROR(pud)				(p4d_ERROR((pud).p4d))
 
 #define p4d_populate(mm, p4d, pud)		do { } while (0)
+#define p4d_populate_safe(mm, p4d, pud)		do { } while (0)
 /*
  * (puds are folded into p4ds so this doesn't get actually called,
  * but the define is needed for a generic inline function.)