move common code file in common directory

remove several unused files
remove mem_block_t that is never used in a different way than a simple heap buffer
move up IP address type and remove duplications of the same struct declaration

openair2/NETWORK_DRIVER/LITE/local.h

@@ -56,7 +56,7 @@
 #define IP2PDCP_FIFO 22
 
 #include "constant.h"
-#include "platform_types.h"
+#include "common/platform_types.h"
 #include "sap.h"
 
 struct cx_entity {

openair2/NETWORK_DRIVER/MESH/local.h

@@ -62,7 +62,7 @@
 #include "constant.h"
 #include "sap.h"
 #include "rrc_nas_primitives.h"
-#include "COMMON/platform_types.h"
+#include "common/platform_types.h"
 
 struct rb_entity {
   nasRadioBearerId_t rab_id;

openair2/NETWORK_DRIVER/UE_IP/local.h

@@ -52,7 +52,7 @@
 #include <net/ndisc.h>
 
 #include "constant.h"
-#include "platform_types.h"
+#include "common/platform_types.h"
 #include "sap.h"
 
 typedef struct ue_ip_priv_s {