Make separate header for nr_pdcp instead of using 4G pdcp

Creates function that have nr_pdcp_ prepended to their name, and change
the signature of some functions for the 5G PDCP:

- nr_pdcp_layer_init()
- nr_pdcp_data_req()
- nr_pdcp_remove_UE()
- nr_pdcp_config_set_security()
- nr_pdcp_remove_UE()
- Make separate functions for nr_pdcp_data_req_srb/drb()

executables/nr-uesoftmodem.c

@@ -59,7 +59,7 @@ unsigned short config_frames[4] = {2,9,11,13};
 
 #include "UTIL/OPT/opt.h"
 #include "enb_config.h"
-#include "pdcp.h"
+#include "LAYER2/nr_pdcp/nr_pdcp_oai_api.h"
 
 #include "intertask_interface.h"
 
@@ -386,7 +386,7 @@ static void init_pdcp(int ue_id) {
   if (get_softmodem_params()->nsa && rlc_module_init(0) != 0) {
     LOG_I(RLC, "Problem at RLC initiation \n");
   }
-  pdcp_layer_init();
+  nr_pdcp_layer_init();
   nr_pdcp_module_init(pdcp_initmask, ue_id);
   pdcp_set_rlc_data_req_func((send_rlc_data_req_func_t) rlc_data_req);
   pdcp_set_pdcp_data_ind_func((pdcp_data_ind_func_t) pdcp_data_ind);