The final "VPL" Power7 boxes that were used for powernv bringup have
been scrapped, meaning there are no machines with ioda1 left.

This patch removes the obvious unused code.
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230613045202.294451-2-joel@jms.id.au