OMCI-lib-go: Generated Class ID's for 418 -> 426 invalid due to ITU document error

The 11/2017 version of ITU G.988 has several class ID values that are off by one from where the should be.   This primarily affects the Ethernet Extended PM 64-bit counters since the incorrect value (426) maps to a different (and valid) ME on most ONUs.

The value should be 425.    The other affected MEs are related to EFM Bonding group but should be corrected as well.

NOTE: A unit test will be added to insure that the 426 for this ME does not creep back into the code since this is from code-generated code.  Work on parsing the 03/2020 version of G.988 is underway as well.