enb: add rf_port to cell list param

we need to make the rf_port a param in the cell list because for CA with
two cells on different EARFNCs, the RF port is different

for two cells without CA on the same EARFCN the RF port is the same

so we need to be able to configure it

Change-Id: I32e83cc34811588757104c5ce1cae7277402addd
diff --git a/sysmocom/defaults.conf b/sysmocom/defaults.conf
index 871a45c..6694652 100644
--- a/sysmocom/defaults.conf
+++ b/sysmocom/defaults.conf
@@ -128,11 +128,13 @@
    - cell_id: 0x01
      pci: 0x01
      dl_earfcn: 2850
+     rf_port: 0
      scell_list: []
      ncell_list: [0x02]
    - cell_id: 0x02
      pci: 0x02
      dl_earfcn: 2850
+     rf_port: 0
      scell_list: []
      ncell_list: [0x01]