Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/powerpc/include/asm/user.h b/arch/powerpc/include/asm/user.h
index 5c0e082..99443b8 100644
--- a/arch/powerpc/include/asm/user.h
+++ b/arch/powerpc/include/asm/user.h
@@ -31,7 +31,7 @@
  *	to write an integer number of pages.
  */
 struct user {
-	struct pt_regs	regs;			/* entire machine state */
+	struct user_pt_regs regs;		/* entire machine state */
 	size_t		u_tsize;		/* text size (pages) */
 	size_t		u_dsize;		/* data size (pages) */
 	size_t		u_ssize;		/* stack size (pages) */