openconfig-platform-types imported but not used in openconfig-if-ethernet.yang:13

[JoseIgnacioTamayo]

In https://github.com/openconfig/public/blob/master/release/models/interfaces/openconfig-if-ethernet.yang#L13, openconfig-platform-types is imported by never used.

This is not wrong, just an inconvenience message when binding. But it might be OK to prune this import.