Add support to CDC-MBIM USB host driver

This driver was created by Adam Porter and posted on NuttX
mailing list at Google Group on Nov 14 2019

net/netdev/netdev_register.c

@@ -55,6 +55,7 @@
 #define NETDEV_PAN_FORMAT   "pan%d"
 #define NETDEV_WLAN_FORMAT  "wlan%d"
 #define NETDEV_WPAN_FORMAT  "wpan%d"
+#define NETDEV_MBIM_FORMAT  "wwan%d"
 
 #if defined(CONFIG_DRIVERS_IEEE80211) /* Usually also has CONFIG_NET_ETHERNET */
 #  define NETDEV_DEFAULT_FORMAT NETDEV_WLAN_FORMAT
@@ -313,6 +314,11 @@ int netdev_register(FAR struct net_driver_s *dev, enum net_lltype_e lltype)
             devfmt   = NETDEV_TUN_FORMAT;
             break;
 #endif
+        case NET_LL_MBIM:
+          dev->d_llhdrlen = 0;
+          dev->d_pktsize = 1200;
+          devfmt = NETDEV_MBIM_FORMAT;
+          break;
 
           default:
             nerr("ERROR: Unrecognized link type: %d\n", lltype);