Fix issues reported on PR #1233

net/Kconfig

@@ -150,6 +150,11 @@ config NET_LOOPBACK_PKTSIZE
 		CONFIG_NET_LOOPBACK_PKTSIZE is zero, meaning that this maximum
 		packet size will be used by loopback driver.
 
+menuconfig NET_MBIM
+        bool "MBIM modem support"
+	depends on USBHOST_CDCMBIM
+	default n
+
 menuconfig NET_SLIP
 	bool "SLIP support"
 	select ARCH_HAVE_NETDEV_STATISTICS

net/netdev/netdev_register.c

@@ -314,11 +314,14 @@ int netdev_register(FAR struct net_driver_s *dev, enum net_lltype_e lltype)
             devfmt   = NETDEV_TUN_FORMAT;
             break;
 #endif
-        case NET_LL_MBIM:
-          llhdrlen = 0;
-          pktsize  = 1200;
-          devfmt   = NETDEV_WWAN_FORMAT;
-          break;
+
+#ifdef CONFIG_NET_MBIM
+          case NET_LL_MBIM:
+            llhdrlen = 0;
+            pktsize  = 1200;
+            devfmt   = NETDEV_WWAN_FORMAT;
+            break;
+#endif
 
           default:
             nerr("ERROR: Unrecognized link type: %d\n", lltype);