Configure complete PDCP in lte-(ue)softmodem

* Instead of partly initializing in read_config_and_init(), everything of
  PDCP is initialized in main() of lte-softmodem
* Omit RC.rrc access in RRU through checking of RC.nb_inst > 0
* Includes FlexRAN, i.e. do not start FlexRAN in RRU
* Function pointers to PDCP functions have to be set explicitly (avoid
  confusion of multiply setting function pointers)

targets/RT/USER/lte-softmodem.h

@@ -35,6 +35,7 @@
 #include "flexran_agent.h"
 #include "s1ap_eNB.h"
 #include "SIMULATION/ETH_TRANSPORT/proto.h"
+#include "proto_agent.h"
 
 /* help strings definition for command line options, used in CMDLINE_XXX_DESC macros and printed when -h option is used */
 #define CONFIG_HLP_RFCFGF        "Configuration file for front-end (e.g. LMS7002M)\n"