When lwIP (CONFIG_NET_LWIP) is used instead of legacy stack (CONFIG_NET), environment flags support associated with network was not built: restore support of "i" and "m" environment flags. Signed-off-by: Benjamin ROBIN <dev@benjarobin.fr> Acked-by: Jerome Forissier <jerome.forissier@linaro.org> Reviewed-by: Tom Rini <trini@konsulko.com>