ppc64: Use arch/powerpc/platforms/powermac for powermac build.

This switches the ARCH=ppc64 build to use arch/powerpc/platforms/powermac
instead of arch/ppc64/kernel/pmac*, and deletes the latter set of files.

Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/platforms/Makefile b/arch/powerpc/platforms/Makefile
index 9b54e80..509622d 100644
--- a/arch/powerpc/platforms/Makefile
+++ b/arch/powerpc/platforms/Makefile
@@ -1,5 +1,9 @@
 ifeq ($(CONFIG_PPC_MERGE),y)
 obj-$(CONFIG_PPC_PMAC)		+= powermac/
+else
+ifeq ($(CONFIG_PPC64),y)
+obj-$(CONFIG_PPC_PMAC)		+= powermac/
+endif
 endif
 obj-$(CONFIG_4xx)		+= 4xx/
 obj-$(CONFIG_85xx)		+= 85xx/