Add Cellular link layer support

1.Add cellular link layer enum definition and register flow
2.Add ioctl flow to set cellular NICs parameters

Signed-off-by: luojun1 <luojun1@xiaomi.com>
Signed-off-by: chao an <anchao@xiaomi.com>

net/netdev/netdev_register.c

@@ -58,6 +58,7 @@
 #define NETDEV_WPAN_FORMAT  "wpan%d"
 #define NETDEV_WWAN_FORMAT  "wwan%d"
 #define NETDEV_CAN_FORMAT   "can%d"
+#define NETDEV_CELL_FORMAT  "cell%d"
 
 #if defined(CONFIG_DRIVERS_IEEE80211) /* Usually also has CONFIG_NET_ETHERNET */
 #  define NETDEV_DEFAULT_FORMAT NETDEV_WLAN_FORMAT
@@ -346,6 +347,15 @@ int netdev_register(FAR struct net_driver_s *dev, enum net_lltype_e lltype)
             break;
 #endif
 
+#ifdef CONFIG_NET_CELLULAR
+          case NET_LL_CELL:
+            llhdrlen = 0;
+            pktsize  = CONFIG_NET_ETH_PKTSIZE;
+            devfmt   = NETDEV_CELL_FORMAT;
+            flags    = IFF_NOARP;
+            break;
+#endif
+
           default:
             nerr("ERROR: Unrecognized link type: %d\n", lltype);
             return -EINVAL;