powerpc/powernv/pci: Remove ioda1 support

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