v2: Updates for MOM6 PR 1668

This PR has updates for building MOM6 with changes from mom-ocean/MOM6#1668

My tests show zero-diff.

Author: mathomp4

MOM6_GEOSPlug/mom6_cmake/CMakeLists.txt

@@ -524,9 +524,6 @@ list( APPEND MOM6_SRCS
    config_src/external/ODA_hooks/ocean_da_types.F90
    config_src/external/ODA_hooks/write_ocean_obs.F90
    # tracer
-   config_src/external/GFDL_ocean_BGC/FMS_coupler_util.F90
-   config_src/external/GFDL_ocean_BGC/generic_tracer.F90
-   config_src/external/GFDL_ocean_BGC/generic_tracer_utils.F90
    config_src/external/GFDL_ocean_BGC/MOM_generic_tracer.F90
    # drifters-particles
    config_src/external/drifters/MOM_particles.F90