powerpc/pci: Remove unimplemented prototypes

The corresponding definitions were deleted in commit 3d5134ee83
("[POWERPC] Rewrite IO allocation & mapping on powerpc64") which
was merged a mere 13 years ago.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200902035138.1762531-1-oohall@gmail.com

arch/powerpc/include/asm/ppc-pci.h

@@ -13,10 +13,6 @@
 
 extern unsigned long isa_io_base;
 
-extern void pci_setup_phb_io(struct pci_controller *hose, int primary);
-extern void pci_setup_phb_io_dynamic(struct pci_controller *hose, int primary);
-
-
 extern struct list_head hose_list;
 
 extern struct pci_dev *isa_bridge_pcidev;	/* may be NULL if no ISA bus */