nr-{ue,}softmodem: Check for correct modes

THere are four possibilities, for the three options (phy_test, do_ra,
nsa):

- None is set -> SA
- Only one is set of each -> corresponding mode

Introduce a function softmodem_verify_mode() to check for these.

executables/nr-uesoftmodem.c

@@ -407,6 +407,9 @@ int main(int argc, char **argv)
 
   get_common_options(uniqCfg, SOFTMODEM_5GUE_BIT);
   CONFIG_CLEARRTFLAG(CONFIG_NOEXITONHELP);
+
+  softmodem_verify_mode(get_softmodem_params());
+
 #if T_TRACER
   T_Config_Init();
 #endif
@@ -461,12 +464,6 @@ int main(int argc, char **argv)
     get_channel_model_mode(uniqCfg);
   }
 
-  if (get_softmodem_params()->do_ra)
-    AssertFatal(get_softmodem_params()->phy_test == 0,"RA and phy_test are mutually exclusive\n");
-
-  if (get_softmodem_params()->sa)
-    AssertFatal(get_softmodem_params()->phy_test == 0,"Standalone mode and phy_test are mutually exclusive\n");
-
   if (!get_softmodem_params()->nsa && get_softmodem_params()->emulate_l1)
     start_oai_nrue_threads();