linux-firmware: update firmware for MT7921 WiFi device

Update binary firmware for MT7921 WiFi devices

File: mediatek/WIFI_MT7961_patch_mcu_1_2_hdr.bin
Version: 20230526130917a
File: mediatek/WIFI_RAM_CODE_MT7961_1.bin
Version: 20230526130958

Signed-off-by: Deren Wu <deren.wu@mediatek.com>
Signed-off-by: Josh Boyer <jwboyer@kernel.org>