The NMBM-Enabled layout did not use fit image,
it just need default process. So it was been removed in platform.sh.
It will fix sysupgrade error for xiaomi,mi-router-wr30u-112m-nmbm.
Signed-off-by: Hank Moretti <mchank9999@gmail.com>
Signed-off-by: Tianling Shen <cnsztl@immortalwrt.org>
(cherry picked from commit 2cab762b71)