[GPU Porting] MOM_forcing_type.F90

[edoyango]

from benchmark:

• extractfluxes1d (0.100000)
• find_ustar_mech_forcing (0.035000)
• copy_common_forcing_fields (0.010000)
• forcing_diagnostics (0.010000)
• get_net_mass_forcing (0.010000)
• set_derived_forcing_fields (0.005000)

from access-om3:

• fluxes_accumulate (11.52s)
• myalloc_2d (0.69s)
• copy_back_forcing_fields (0.42s)
• mech_forcing_diags (0.12s)
• set_net_mass_forcing (0.07s)
• register_forcing_type_diags (0.06s)
• forcing_accumulate (0.05s)
• allocate_forcing_by_group (0.01s)
• allocate_mech_forcing_by_group (0.01s)