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/siginfo_32.h

@@ -0,0 +1,17 @@
+#ifndef _SPARC_SIGINFO_H
+#define _SPARC_SIGINFO_H
+
+#define __ARCH_SI_UID_T		unsigned int
+#define __ARCH_SI_TRAPNO
+
+#include <asm-generic/siginfo.h>
+
+#define SI_NOINFO	32767		/* no information in siginfo_t */
+
+/*
+ * SIGEMT si_codes
+ */
+#define EMT_TAGOVF	(__SI_FAULT|1)	/* tag overflow */
+#define NSIGEMT		1
+
+#endif /* !(_SPARC_SIGINFO_H) */