update MOM6 to its main branch 20211220 commit

[jiandewang]

MOM6 main branch has been updated on 20211220 which contains stochastic physics code further modification (see detail at mom-ocean/MOM6#1538).
Need to make corresponding updating in EMC MOM6 (MOM6 issue at NOAA-EMC/MOM6#80) and UFS repository.

[junwang-noaa]

Code is committed.