AppNote: RZ/A1 Realtek WiFi module startup guide

Contents:
•Introduce how the JORJIN WG6031P00 WiFi board working on RZ/A1 RSK board.
•Enable the Wi-Fi module(RTL8189EM) with SDIO driver in xipLinux.
•Using wireless tool(iw & wpa_supplicant) to control Wi-Fi module.
•Implement DHCP client on RSK for getting IP from AP.