FATES_FUEL_AMOUNT(_AP) incorrectly kg instead of kg/m2

[samsrabin]

The units of both these output variables are kg/m2. However, when they're calculated in FatesHistoryInterfaceMod, they're calculated as kg. The multiplications by cpatch%area in the below snippets need to be followed by divisions by site area (for FATES_FUEL_AMOUNT) or age class area (for FATES_FUEL_AMOUNT_AP), but those divisions never happen.

FATES_FUEL_AMOUNT:

hio_sum_fuel_si(io_si)             = hio_sum_fuel_si(io_si) + cpatch%sum_fuel * cpatch%area * AREA_INV

FATES_FUEL_AMOUNT_AP:

 hio_fire_sum_fuel_si_age(io_si, cpatch%age_class) = hio_fire_sum_fuel_si_age(io_si, cpatch%age_class) +  &
    cpatch%sum_fuel * cpatch%area * AREA_INV

There may be other variables with this problem.

(Originally discovered as part of #1205, but this is a more fundamental issue.)

[samsrabin]

No; cpatch%sum_fuel is kg/m2, not kg.