Add missing device names to enb.conf.example

The enb.conf.example config was missing the options "soapy" and "zmq" for device_name.

srsenb/enb.conf.example

@@ -50,7 +50,8 @@ drb_config = drb.conf
 # Optional parameters:
 # dl_freq:            Override DL frequency corresponding to dl_earfcn
 # ul_freq:            Override UL frequency corresponding to dl_earfcn (must be set if dl_freq is set)
-# device_name:        Device driver family. Supported options: "auto" (uses first found), "UHD" or "bladeRF" 
+# device_name:        Device driver family.
+#                     Supported options: "auto" (uses first found), "UHD", "bladeRF", "soapy" or "zmq".
 # device_args:        Arguments for the device driver. Options are "auto" or any string.
 #                     Default for UHD: "recv_frame_size=9232,send_frame_size=9232"
 #                     Default for bladeRF: ""