Huawei.MA5600T. Add Load OID for GPON interface metrics.
See merge request !4061 (merged)
(cherry picked from commit c7df1558)
021e8e58 Huawei.MA5600T. Add Load OID for GPON interface metrics. 30214fe0 Huawei.MA5600T.get_version. Add 'Patch Version'. caafaac1 Add Packet metrics. 637e8e5f Add 'Interface | Errors | In' metric for gpon ports.