Use parametrized scenario to set ENB num_prb

Change-Id: Iec7d7e6312aee6f4e4ce6710bc78a144beff2f39
diff --git a/example/scenarios/mod-enb-nprb@.conf b/example/scenarios/mod-enb-nprb@.conf
new file mode 100644
index 0000000..f17347c
--- /dev/null
+++ b/example/scenarios/mod-enb-nprb@.conf
@@ -0,0 +1,3 @@
+modifiers:
+  enb:
+  - num_prb: ${param1}