Fix 'make headers_check' on m32r

> asm-m32r/page.h requires asm-generic/memory_model.h, which does not exist
> asm-m32r/ptrace.h requires asm/m32r.h, which does not exist
> asm-m32r/signal.h requires linux/linkage.h, which does not exist
> asm-m32r/unistd.h requires asm/syscall.h, which does not exist
> asm-m32r/user.h requires asm/processor.h, which does not exist

Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

include/asm-m32r/unistd.h

@@ -3,8 +3,6 @@
 
 /* $Id$ */
 
-#include <asm/syscall.h>	/* SYSCALL_* */
-
 /*
  * This file contains the system call numbers.
  */
@@ -303,6 +301,8 @@
  * <asm-m32r/errno.h>
  */
 
+#include <asm/syscall.h>	/* SYSCALL_* */
+
 #define __syscall_return(type, res) \
 do { \
 	if ((unsigned long)(res) >= (unsigned long)(-(124 + 1))) { \