This ports the existing 64-bit mechanism to 32-bit, thus series
of 64 tlbie's followed by a sync like some versions of Darwin
(ab)use will result in a single flush.

We apply a pending flush on any sync instruction though, as Darwin
doesn't use tlbsync on non-SMP systems.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>