dts: jh7110: fix memory definitions

The L2LIM is 2MB in size, see:
https://doc-en.rvspace.org/JH7110/TRM/JH7110_TRM/u74_memory_map.html


Rename it since there are other memory blocks such as the DTIM for the S7.

Signed-off-by: Daniel Maslowski <info@orangecms.org>