The addresses were read from the 'config' partition, which would not always
contain the addresses at the same offsets, depending on the stock firmware
version used before flashing LEDE. Change this to get the addresses from
the 'product-info' partition, which is read-only.
Reported-and-tested-by: Andreas Ziegler <ml@andreas-ziegler.de>
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
