Reimplement nFAPI message exchange after msgDataTx removal

Reimplement nFAPI message exchange between L1 and L2 following the
changes in parent commit removing msgDataTx.

Avoid direct calls and use NR_IF_module fptrs to avoid linking problems.
allowing to remove some function definitions that are not needed.

openair2/NR_PHY_INTERFACE/NR_IF_Module.h

@@ -91,7 +91,7 @@ typedef struct {
 // Downlink slot P7
 
 
-typedef struct {
+typedef struct NR_Sched_Rsp {
   /// the ID of this sched_response - used by sched_reponse memory management
   int sched_response_id;
   /// Module ID
@@ -137,8 +137,6 @@ NR_IF_Module_t *NR_IF_Module_init(int Mod_id);
 
 void NR_IF_Module_kill(int Mod_id);
 
-void NR_UL_indication(NR_UL_IND_t *UL_INFO);
-
 /*Interface for Downlink, transmitting the DLSCH SDU, DCI SDU*/
 void NR_Schedule_Response(NR_Sched_Rsp_t *Sched_INFO);