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/include/asm-powerpc/mpic.h b/include/asm-powerpc/mpic.h
index f1e24f4..6b558ae 100644
--- a/include/asm-powerpc/mpic.h
+++ b/include/asm-powerpc/mpic.h
@@ -1,3 +1,6 @@
+#ifndef _ASM_POWERPC_MPIC_H
+#define _ASM_POWERPC_MPIC_H
+
 #include <linux/irq.h>
 
 /*
@@ -277,3 +280,5 @@
 
 /* global mpic for pSeries */
 extern struct mpic *pSeries_mpic;
+
+#endif	/* _ASM_POWERPC_MPIC_H */