Update KConfig

components/net/KConfig

 menu "Network stack"
 
-menu "Light weight TCP/IP stack"
+menu "light weight TCP/IP stack"
 config RT_USING_LWIP
     bool "Enable lwIP stack"
     default n
@@ -82,10 +82,6 @@ config RT_USING_LWIP
             bool "PPPoS protocol"
             default n
 
-        config RT_LWIP_USING_RT_MEM
-            bool "Using RT-Thread Memory Management for LWIP"
-            default y
-        
         config RT_LWIP_PBUF_NUM
             int "the number of PBUF"
             default 16
@@ -169,8 +165,11 @@ endmenu
 
 source "$RTT_DIR/components/net/freemodbus/KConfig"
 
+if RT_USING_LWIP
 config RT_USING_NETUTILS
     bool "Enable net utils"
     default n
 
+#endif
+
 endmenu