sparc, sparc64: use arch/sparc/include

The majority of this patch was created by the following script:

***
ASM=arch/sparc/include/asm
mkdir -p $ASM
git mv include/asm-sparc64/ftrace.h $ASM
git rm include/asm-sparc64/*
git mv include/asm-sparc/* $ASM
sed -ie 's/asm-sparc64/asm/g' $ASM/*
sed -ie 's/asm-sparc/asm/g' $ASM/*
***

The rest was an update of the top-level Makefile to use sparc
for header files when sparc64 is being build.
And a small fixlet to pick up the correct unistd.h from
sparc64 code.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

arch/sparc/include/asm/percpu_64.h

@@ -0,0 +1,28 @@
+#ifndef __ARCH_SPARC64_PERCPU__
+#define __ARCH_SPARC64_PERCPU__
+
+#include <linux/compiler.h>
+
+register unsigned long __local_per_cpu_offset asm("g5");
+
+#ifdef CONFIG_SMP
+
+extern void real_setup_per_cpu_areas(void);
+
+extern unsigned long __per_cpu_base;
+extern unsigned long __per_cpu_shift;
+#define __per_cpu_offset(__cpu) \
+	(__per_cpu_base + ((unsigned long)(__cpu) << __per_cpu_shift))
+#define per_cpu_offset(x) (__per_cpu_offset(x))
+
+#define __my_cpu_offset __local_per_cpu_offset
+
+#else /* ! SMP */
+
+#define real_setup_per_cpu_areas()		do { } while (0)
+
+#endif	/* SMP */
+
+#include <asm-generic/percpu.h>
+
+#endif /* __ARCH_SPARC64_PERCPU__ */