Dynamically considering pointer size to support multiple platforms
This change helps filling bt_mesh_adv buffer correctly while sending
secure beacons (on Linux platform).
#define BT_MESH_ADV_DATA_SIZE 31
/* The user data is a pointer (4 bytes) to struct bt_mesh_adv */
-#define BT_MESH_ADV_USER_DATA_SIZE 4
+#define BT_MESH_ADV_USER_DATA_SIZE (sizeof(struct bt_mesh_adv *))
#define BT_MESH_MBUF_HEADER_SIZE (sizeof(struct os_mbuf_pkthdr) + \
BT_MESH_ADV_USER_DATA_SIZE +\
