Fix Const pointer wrong use.

Change-Id: I32e7c4865fa08f7b8f9814cf68c85859fb2bd65a

Author: Juha Heiskanen

nanostack/mac_common_defines.h

@@ -78,7 +78,7 @@ typedef struct mlme_security_s {
  * This structure encapsulates security related variables,
  */
 typedef struct mac_header_IE_s {
-    const uint8_t *content_ptr;   /**< Content data */
+    uint8_t *content_ptr;   /**< Content data */
     unsigned length:7;      /**< Element length 0- 127 */
     uint8_t id;             /**< Element ID */
 } mac_header_IE_t;
@@ -94,7 +94,7 @@ typedef struct mac_header_IE_s {
  * This structure encapsulates security related variables,
  */
 typedef struct mac_payload_IE_s {
-    const uint8_t *content_ptr;   /**< Content data */
+    uint8_t *content_ptr;   /**< Content data */
     unsigned length:11;     /**< Element length 0- 2047 */
     unsigned id:4;          /**< Group ID */
 } mac_payload_IE_t;