The RTL931x devices have an other register that describes the
current RAM configuration. Enhance the identification routine.
Tested on LGS352C (RTL9311).
Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Link: https://github.com/openwrt/openwrt/pull/19284
Signed-off-by: Robert Marko <robimarko@gmail.com>