ubifs: Fix journal replay wrt. xattr nodes

Backport commit 1cb51a15b576 ("ubifs: Fix journal replay wrt. xattr
nodes") from the Linux Kernel, which has the following Signed-off-by
line:
Signed-off-by: Richard Weinberger <richard@nod.at>

For U-Boot, after comapring with the upstream commit:
Signed-off-by: Tom Rini <trini@konsulko.com>