Move include guard to the top

Having explicit include above the douible-include guard defines is
potential source for hard to track bugs. Let's move it inside the guard
statement.

Change-Id: I5114a63ce00b03c8eed23565d52969250bd505cc
Related: OS#1539

src/csn1.h

@@ -25,15 +25,15 @@
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  */
 
+#ifndef _PACKET_CSN1_H_
+#define _PACKET_CSN1_H_
+
 extern "C" {
 #include <osmocom/core/bitvec.h>
 }
 
 #include <iostream>
 #include <cstdlib>
-#ifndef _PACKET_CSN1_H_
-#define _PACKET_CSN1_H_
-
 
 #define MIN(a,b) (((a)<(b))?(a):(b))
 //#define max(a,b) (((a)>(b))?(a):(b))

src/gsm_rlcmac.h

@@ -29,11 +29,12 @@
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  */
 
+#ifndef __PACKET_GSM_RLCMAC_H__
+#define __PACKET_GSM_RLCMAC_H__
+
 #include "csn1.h"
 #include <iostream>
 #include <cstdlib>
-#ifndef __PACKET_GSM_RLCMAC_H__
-#define __PACKET_GSM_RLCMAC_H__
 
 #ifndef PRE_PACKED
 #define PRE_PACKED