powerpc: Move remaining .c files from arch/ppc64 to arch/powerpc

This also deletes the now-unused Makefiles under arch/ppc64.

Both of the files moved over could use some merging, but for now I
have moved them as-is and arranged for them to be used only in 64-bit
kernels.  For 32-bit kernels we still use arch/ppc/kernel/idle.c and
drivers/char/generic_nvram.c as before.

Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 99dbea8..987036b 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -125,11 +125,11 @@
 head-$(CONFIG_PPC_FPU)		+= arch/powerpc/kernel/fpu.o
 
 core-y				+= arch/powerpc/kernel/ \
-				   arch/$(OLDARCH)/kernel/ \
 				   arch/powerpc/mm/ \
 				   arch/powerpc/lib/ \
 				   arch/powerpc/sysdev/ \
 				   arch/powerpc/platforms/
+core-$(CONFIG_PPC32)		+= arch/ppc/kernel/
 core-$(CONFIG_MATH_EMULATION)	+= arch/ppc/math-emu/
 core-$(CONFIG_XMON)		+= arch/powerpc/xmon/
 core-$(CONFIG_APUS)		+= arch/ppc/amiga/
@@ -165,7 +165,7 @@
   @echo '                    (your) ~/bin/installkernel or'
   @echo '                    (distribution) /sbin/installkernel or'
   @echo '                    install to $$(INSTALL_PATH) and run lilo'
-  @echo '  *_defconfig     - Select default config from arch/$(ARCH)/ppc/configs'
+  @echo '  *_defconfig     - Select default config from arch/$(ARCH)/configs'
 endef
 
 archclean: