powerpc/pci: Remove pcibios_setup_bus_devices()

With the previous patch applied pcibios_setup_device() will always be run
when pcibios_bus_add_device() is called. There are several code paths where
pcibios_setup_bus_device() is still called (the PowerPC specific PCI
hotplug support is one) so with just the previous patch applied the setup
can be run multiple times on a device, once before the device is added
to the bus and once after.

There's no need to run the setup in the early case any more so just
remove it entirely.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191028085424.12006-3-oohall@gmail.com