modules: bump OpenWrt

594f731e04 ramips: fix Archer C20i wireless MAC address
037a151c56 ramips: fix Archer C2 v1 5GHz MAC address
3e8b66e0da ramips: add system LED indicators for TP-Link C20i
80e0b97d07 ramips: convert TP-Link MT7620 boards to tpt trigger
a2e2c40b5e mt76: update to the latest openwrt-19.07 version
1f927bd2f0 ramips: fix inverted reset button for Ravpower WD03

Compile-tested: ramips-mt7621
Run-tested: ramips-mt7621