powerpc: switch to GENERIC_PCI_IOMAP

powerpc copied pci_iomap from generic code, probably to avoid
pulling the rest of iomap.c in.  Since that's in
a separate file now, we can reuse the common implementation.

The only difference is handling of nocache flag,
that turns out to be done correctly by the
generic code since arch/powerpc/include/asm/io.h
defines ioremap_nocache same as ioremap.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 951e18f..6ffe3df 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -710,6 +710,7 @@
 	default PCI_PERMEDIA if !4xx && !CPM2 && !8xx
 	default PCI_QSPAN if !4xx && !CPM2 && 8xx
 	select ARCH_SUPPORTS_MSI
+	select GENERIC_PCI_IOMAP
 	help
 	  Find out whether your system includes a PCI bus. PCI is the name of
 	  a bus system, i.e. the way the CPU talks to the other stuff inside