powerpc: Move include files to arch/powerpc/include/asm

from include/asm-powerpc.  This is the result of a

mkdir arch/powerpc/include/asm
git mv include/asm-powerpc/* arch/powerpc/include/asm

Followed by a few documentation/comment fixups and a couple of places
where <asm-powepc/...> was being used explicitly.  Of the latter only
one was outside the arch code and it is a driver only built for powerpc.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/include/asm/percpu.h

@@ -0,0 +1,24 @@
+#ifndef _ASM_POWERPC_PERCPU_H_
+#define _ASM_POWERPC_PERCPU_H_
+#ifdef __powerpc64__
+#include <linux/compiler.h>
+
+/*
+ * Same as asm-generic/percpu.h, except that we store the per cpu offset
+ * in the paca. Based on the x86-64 implementation.
+ */
+
+#ifdef CONFIG_SMP
+
+#include <asm/paca.h>
+
+#define __per_cpu_offset(cpu) (paca[cpu].data_offset)
+#define __my_cpu_offset local_paca->data_offset
+#define per_cpu_offset(x) (__per_cpu_offset(x))
+
+#endif /* CONFIG_SMP */
+#endif /* __powerpc64__ */
+
+#include <asm-generic/percpu.h>
+
+#endif /* _ASM_POWERPC_PERCPU_H_ */