Makefile fix to handle multiple routes towards RAN

Change-Id: I224e5af77487c5e6f2cc3d647307fd9512bc9266
diff --git a/Makefile b/Makefile
index 5f2c186..85e7d93 100644
--- a/Makefile
+++ b/Makefile
@@ -49,7 +49,7 @@
 ifeq ($(DATA_IFACE), data)
 	RAN_SUBNET := 192.168.251.0/24
 else
-	RAN_SUBNET := $(shell ip route | grep $${DATA_IFACE} | awk '/kernel/ {print $$1}')
+	RAN_SUBNET := $(shell ip route | grep $${DATA_IFACE} | awk '/kernel/ {print $$1}' | head -1)
 	DATA_IFACE_PATH := $(shell find /*/systemd/network -maxdepth 1 -not -type d -name '*$(DATA_IFACE).network' -print)
 	DATA_IFACE_CONF ?= $(shell basename $(DATA_IFACE_PATH)).d
 endif