Add binary firmware for MT7921 based devices

File: mediatek/WIFI_MT7961_patch_mcu_1_2_hdr.bin
Version: 20210122002654a
File: mediatek/WIFI_RAM_CODE_MT7961_1.bin
Version: 20210122002730
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Josh Boyer <jwboyer@kernel.org>