Some FATES-SP configurations are calling patch%itype

The tests:
SMS_D.1x1_brazil.I2000Clm60FatesSpCruRsGs.derecho_gnu.clm-FatesColdDryDepSatPhen and ERP_P128x2_Ld30.f45_f45_mg37.I2000Clm60FatesSpCruRsGs.derecho_intel.clm-FatesColdSatPhen

generate a run fail with the following error message:

```
At line 879 of file /glade/u/home/rgknox/ctsm/src/main/subgridWeightsMod.F90
dec2438.hsn.de.hpc.ucar.edu 0: Fortran runtime error: Index '-9998' of dimension 2 of array 'subgrid_weights_diagnostics%pct_nat_pft' below lower bound of 1
dec2438.hsn.de.hpc.ucar.edu 0:
```

Here is line [879](https://github.com/ESCOMP/CTSM/blob/ctsm5.3.043/src/main/subgridWeightsMod.F90#L879)

This issue is newly generated with issue #2933 and PR: #2935 , that PR sets itype to a bogus value that will trigger this type of error, so that it is not inappropriately used.

When fates is active, the itype should never be used, even in SP. Yes, with FATES-SP we do associate patches with a specific PFT, but FATES does not follow the same PFT indexing convention that is found in the surface file, so associating a patch with a pft on the clm-side is meaningless and impossible.