[S390] Add missing ifndef/define to include/asm-s390/sysinfo.h.

In order to protect against compile breakage in case the header file
gets included twice.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/include/asm-s390/sysinfo.h b/include/asm-s390/sysinfo.h
index abe10ae..79d0134 100644
--- a/include/asm-s390/sysinfo.h
+++ b/include/asm-s390/sysinfo.h
@@ -11,6 +11,9 @@
  *		 Christian Borntraeger <borntraeger@de.ibm.com>
  */
 
+#ifndef __ASM_S390_SYSINFO_H
+#define __ASM_S390_SYSINFO_H
+
 struct sysinfo_1_1_1 {
 	char reserved_0[32];
 	char manufacturer[16];
@@ -114,3 +117,5 @@
 		: "cc", "memory");
 	return r0;
 }
+
+#endif /* __ASM_S390_SYSINFO_H */