Modify the reg value returned by the modeminfo script and Add the codes of Chinese telecom operators

[Y0518]

Add the codes of the three major Chinese telecom operators and their corresponding English name packages/net/modeminfo/root/usr/share/modeminfo/mccmnc.dat

Modify the reg value returned by the modeminfo script to resolve the issue of the operator displaying denied when using a pure data sim-card in luci-app-modeminfo. packages/net/modeminfo/root/usr/share/modeminfo/scripts/modeminfo