mediatek: fix nmbm configuration mismatch (Xiaomi AX3000t)

mediatek: fix nmbm configuration mismatch (Xiaomi AX3000t)

This commit fixes nmbm configuration mismatch error on Xiaomi AX3000t
with Winbond W25N01KVZEIR spi-nand:
'''
[    0.786783] NMBM configuration mismatch
'''

Root cause:
1. U-Boot W25N01KV spi-nand driver ia compiled with 64B OOB size for the
   chip and store this size in the nmbm signature;
2. Linux W25N01KV driver use 96B OOB.

The change doesn't affect AX3000t variants with other spi-nand chips
(ESMT, Foresee) because their Linux drivers use 64B OOB.

Fixes: openwrt#16972
Tested-by: Aleksandr Danilov <sc16me@gmail.com>
Signed-off-by: Mikhail Zhilkin <csharper2005@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/17549
Signed-off-by: Robert Marko <robimarko@gmail.com>