Pull powerpc fixes from Ben Herrenschmidt:
"Here are a couple of small powerpc fixes. They aren't new bugs (and
they are both CCed to stable) but I didn't see the point of sitting on
the fixes any longer."
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
powerpc: Add missing NULL terminator to avoid boot panic on PPC40x
powerpc/vdso: Remove redundant locking in update_vsyscall_tz()