We forgot to do gen_update_nip() for these like we do with other
helpers. Fix this, but in a more efficient way by passing the RA
to the accessors instead so the overhead is only taken on faults.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>