modules: update openwrt

51881b2eb9 mediatek: add support for Routerich AX3000
18d7962f7b ramips: add support for Rostelecom RT-FE-1A
f6fb6bb2ba ramips: mt7621: use lzma-loader for Sercomm NA502
9a7b14dcfe mediatek: enable mt7981-wo-firmware package by default
9325da80ab mac80211: fix a race condition related to enabling fast-xmit
b0fc8b47e0 netifd: update to Git openwrt-23.05 (2024-01-04)
5cc1918a7a dropbear: increase default receive window size
60e49cf170 ramips: fix label-mac for Xiaomi RA75