update lwipdhcpd scons groupname

components/net/lwip_dhcpd/SConscript

@@ -5,6 +5,6 @@ src = Glob('*.c')
 
 CPPPATH = [cwd]
 
-group = DefineGroup('LwIP', src, depend = ['RT_USING_LWIP', 'LWIP_USING_DHCPD'], CPPPATH = CPPPATH)
+group = DefineGroup('lwIP', src, depend = ['RT_USING_LWIP', 'LWIP_USING_DHCPD'], CPPPATH = CPPPATH)
 
 Return('group')