powerpc/32: Restore previous version of 32-bit PCI code

When I removed the powermac support from arch/ppc/kernel/pci.c,
I overlooked the fact that that file is used in 32-bit ARCH=powerpc
builds.  To prevent problems in future, restore the original version
of that file as arch/powerpc/kernel/pci_32.c, and use that.
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/Makefile

@@ -60,7 +60,8 @@ obj-$(CONFIG_MODULES)		+= $(module-y)
 
 pci64-$(CONFIG_PPC64)		+= pci_64.o pci_dn.o pci_iommu.o \
 				   pci_direct_iommu.o iomap.o
-obj-$(CONFIG_PCI)		+= $(pci64-y)
+pci32-$(CONFIG_PPC32)		:= pci_32.o
+obj-$(CONFIG_PCI)		+= $(pci64-y) $(pci32-y)
 kexec-$(CONFIG_PPC64)		:= machine_kexec_64.o crash.o
 kexec-$(CONFIG_PPC32)		:= machine_kexec_32.o
 obj-$(CONFIG_KEXEC)		+= machine_kexec.o $(kexec-y)

arch/ppc/kernel/Makefile

@@ -40,7 +40,6 @@ obj-$(CONFIG_6xx)		+= l2cr.o cpu_setup_6xx.o
 obj-$(CONFIG_SOFTWARE_SUSPEND)	+= swsusp.o
 obj-$(CONFIG_MODULES)		+= module.o
 obj-$(CONFIG_NOT_COHERENT_CACHE)	+= dma-mapping.o
-obj-$(CONFIG_PCI)		+= pci.o
 obj-$(CONFIG_KGDB)		+= ppc-stub.o
 obj-$(CONFIG_TAU)		+= temp.o
 ifndef CONFIG_E200