linux-firmware: add firmware for mt76x2

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Hua Shao <hua.shao@mediatek.com>
[kyle: fixed permissions on mt7662*.bin]
Signed-off-by: Kyle McMartin <kyle@kernel.org>

WHENCE

@@ -3426,3 +3426,15 @@ File: rockchip/dptx.bin
 Version: 3.1
 
 Licence: Redistributable. See LICENCE.rockchip for details.
+
+---------------------------------------------------------------------------
+
+Driver: mt76x2e - MediaTek MT76x2 Wireless MACs
+
+File: mt7662.bin
+Version: 1.9
+
+File: mt7662_rom_patch.bin
+Version: 0.0.2_P69
+
+Licence: Redistributable. See LICENCE.ralink_a_mediatek_company_firmware for details