loongson/mirror: links for electrum-vtc

loongson/mirror Electrum-VTC-2.9.3.3.tar.gz
loongson/mirror Electrum-VTC-2.9.3.2.tar.gz
loongson/mirror Electrum-VTC-2.9.3.1.post1.tar.gz
loongson/mirror Electrum-VTC-2.9.3.1.tar.gz