FATES cases fail when using crop datasets

### Brief summary of bug

FATES cases fail when you point to surface datasets with crop rather than the 16pft versions.

### General bug information

**CTSM version you are using:** ctsm5.1.dev057-11-g96d6865e7

**Does this bug cause significantly incorrect results in the model's science?**No

**Configurations affected:** FATES cases

### Details of bug

Following cases fail when pointing to surface datasets with crop on them:

ERS_D_Ld5.f09_g17.I2000Clm45Fates.cheyenne_intel.clm-FatesColdDef.GC.ctsm51d58acl_int
ERS_D_Ld5.f09_g17.I2000Clm50Fates.cheyenne_intel.clm-FatesColdDef.GC.ctsm51d58acl_int
ERS_D_Ld5.f10_f10_mg37.I2000Clm45Fates.cheyenne_intel.clm-FatesColdDef.GC.ctsm51d58acl_int
ERS_D_Ld5.f10_f10_mg37.I2000Clm50Fates.cheyenne_intel.clm-FatesColdDef.GC.ctsm51d58acl_int
ERS_Ld9.f10_f10_mg37.I2000Clm50FatesCru.cheyenne_intel.clm-FatesColdDefCH4.GC.ctsm51d58acl_int
SMS_D_Ld5.f10_f10_mg37.I2000Clm45Fates.cheyenne_gnu.clm-FatesColdDef.GC.ctsm51d58acl_gnu
SMS_D_Ld5.f10_f10_mg37.I2000Clm45Fates.cheyenne_intel.clm-FatesColdDef.GC.ctsm51d58acl_int
SMS_D_Ld5.f10_f10_mg37.I2000Clm50Fates.cheyenne_gnu.clm-FatesColdDef.GC.ctsm51d58acl_gnu
SMS_D_Ld5.f10_f10_mg37.I2000Clm50Fates.cheyenne_intel.clm-FatesColdDef.GC.ctsm51d58acl_int
SMS_D_Ld5.f45_f45_mg37.I2000Clm45Fates.cheyenne_intel.clm-FatesColdDef.GC.ctsm51d58acl_int
SMS_D_Ld5.f45_f45_mg37.I2000Clm51Fates.cheyenne_intel.clm-FatesColdDef.GC.ctsm51d58acl_int
SMS_D_Lm6.f45_f45_mg37.I2000Clm45Fates.cheyenne_intel.clm-FatesColdDef.GC.ctsm51d58acl_int
SMS_D_Lm6.f45_f45_mg37.I2000Clm50Fates.cheyenne_intel.clm-FatesColdDef.GC.ctsm51d58acl_int
SMS_D_Lm6_P144x1.f45_f45_mg37.I2000Clm50Fates.cheyenne_intel.clm-FatesColdDef.GC.ctsm51d58acl_int
SMS_Ld5.f10_f10_mg37.I2000Clm45Fates.cheyenne_intel.clm-FatesColdDef.GC.ctsm51d58acl_int
SMS_Ld5.f10_f10_mg37.I2000Clm50Fates.cheyenne_gnu.clm-FatesColdDef.GC.ctsm51d58acl_gnu
SMS_Ld5.f10_f10_mg37.I2000Clm50Fates.cheyenne_intel.clm-FatesColdDef.GC.ctsm51d58acl_int
SMS_Ld5.f19_g17.I2000Clm45Fates.cheyenne_intel.clm-FatesColdDef.GC.ctsm51d58acl_int
SMS_Ld5.f19_g17.I2000Clm50Fates.cheyenne_intel.clm-FatesColdDef.GC.ctsm51d58acl_int

### Important details of your setup / configuration so we can reproduce the bug

SMS_D_Ld5.f10_f10_mg37.I2000Clm50Fates.cheyenne_intel.clm-FatesColdDef

fsurdat = '/glade/p/cesmdata/cseg/inputdata/lnd/clm2/surfdata_map/release-clm5.0.18/surfdata_10x15_hist_78pfts_CMIP6_simyr2000_c190214.nc'

### Important output or errors that show the problem

```
Attempting to read surface boundary data .....
(GETFIL): attempting to find local file
surfdata_10x15_hist_78pfts_CMIP6_simyr2000_c190214.nc
(GETFIL): using
/glade/p/cesmdata/cseg/inputdata/lnd/clm2/surfdata_map/release-clm5.0.18/surfda
ta_10x15_hist_78pfts_CMIP6_simyr2000_c190214.nc
check_var: variable xc is not on dataset
surfrd_get_data lon_var = LONGXY lat_var =LATIXY
WARNING: New CFT-based format surface datasets should be run with
create_crop_landunit=T
WARNING: When fates is on we allow new CFT based surface datasets
to be used with create_crop_land FALSE
check_dim_size ERROR: mismatch of input dimension 64
with expected value 2 for variable cft
ERROR:
ERROR in /glade/work/erik/ctsm_worktrees/misc_PPE_answer_changes/src/main/ncdio
_pio.F90.in at line 409
```