microblaze/PCI: Remove pcibios_setup_bus_{self/devices} dead code

01cf9d52 ("microblaze/PCI: Support generic Xilinx AXI PCIe Host Bridge
IP driver") removed pcibios calls to:

  pcibios_setup_bus_self()
  pcibios_setup_bus_devices()

Given that pcibios_fixup_bus() was the only caller of those functions they
have now become dead code (along with the functions they were calling in
turn), so they can be removed.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
[bhelgaas: remove "Fixup resources of a PCI<->PCI bridge" comment]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Cc: Bharat Kumar Gogada <bharatku@xilinx.com>
Cc: Ravi Kiran Gummaluri <rgummal@xilinx.com>