powerpc/pci: Support per-aperture memory offset

The PCI core supports an offset per aperture nowadays but our arch
code still has a single offset per host bridge representing the
difference betwen CPU memory addresses and PCI MMIO addresses.

This is a problem as new machines and hypervisor versions are
coming out where the 64-bit windows will have a different offset
(basically mapped 1:1) from the 32-bit windows.

This fixes it by using separate offsets. In the long run, we probably
want to get rid of that intermediary struct pci_controller and have
those directly stored into the pci_host_bridge as they are parsed
but this will be a more invasive change.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/pci-bridge.h b/arch/powerpc/include/asm/pci-bridge.h
index 0694f73..8b11b5b 100644
--- a/arch/powerpc/include/asm/pci-bridge.h
+++ b/arch/powerpc/include/asm/pci-bridge.h
@@ -39,11 +39,6 @@
 	resource_size_t io_base_phys;
 	resource_size_t pci_io_size;
 
-	/* Some machines (PReP) have a non 1:1 mapping of
-	 * the PCI memory space in the CPU bus space
-	 */
-	resource_size_t pci_mem_offset;
-
 	/* Some machines have a special region to forward the ISA
 	 * "memory" cycles such as VGA memory regions. Left to 0
 	 * if unsupported
@@ -86,6 +81,7 @@
 	 */
 	struct resource	io_resource;
 	struct resource mem_resources[3];
+	resource_size_t mem_offset[3];
 	int global_number;		/* PCI domain number */
 
 	resource_size_t dma_window_base_cur;