Instead of using the hash of the Github-generated tarball use the
hash of the tarball generated by the OpenWrt build system (in this
case they are different, unfortunately).
Reported-by: Chen Minqiang <ptpt52@gmail.com>
Fixes: 07dbeb430e ("arm-trusted-firmware-mediatek: update to sources of 2023-07-24")
Signed-off-by: Daniel Golle <daniel@makrotopia.org>