econet: en75_bmt: honor per-partition enable-remap

econet: en75_bmt: honor per-partition enable-remap

The per-partition branch of w_init() tested econet,enable-remap on the parent
nand node (np) instead of the partition being iterated (part_np). That branch
only runs when np does not carry the property, so the test was always false and
the loop skipped every partition. As a result econet,enable-remap on a
partition node was a silent no-op: no partition ever registered a remap range,
and "enable-remap set for ..." was never printed.

Read the property from part_np so per-partition enable-remap works as
documented. Boards that place the property on a partition now register that
range; boards that place it on the nand node are unaffected.

Signed-off-by: Ahmed Naseef <naseefkm@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/24399
Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>