powerpc: clean up after powermac build merge

Complete moving arch/ppc64/kernel/mpic.h,
        include/asm-ppc/reg.h, include/asm-ppc64/kdebug.h
	        and include/asm-ppc64/kprobes.h
Add arch/powerpc/platforms/Makefile and use it from
	arch/powerpc/Makefile
Introduce OLDARCH temporarily so we can point back to
	the originating architecture

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
diff --git a/arch/ppc64/kernel/pSeries_smp.c b/arch/ppc64/kernel/pSeries_smp.c
index d2c7e2c..5d1ed85 100644
--- a/arch/ppc64/kernel/pSeries_smp.c
+++ b/arch/ppc64/kernel/pSeries_smp.c
@@ -46,8 +46,8 @@
 #include <asm/rtas.h>
 #include <asm/plpar_wrappers.h>
 #include <asm/pSeries_reconfig.h>
+#include <asm/mpic.h>
 
-#include "mpic.h"
 #include "bpa_iic.h"
 
 #ifdef DEBUG