Remove variables to exclude for fates_sp user mod

[glemieux]

Description of changes

Removes the hist_fexl fields in the fates_sp user mod. This should be coordinated with NGEET/fates#1568, which adds satellite phenology mode aware logic to automatically set the active/inactive FATES history variables.

Specific notes

Contributors other than yourself, if any:
@mvdebolskiy

CTSM issues resolved or otherwise addressed, if any:

• (Replace this text, including GitHub issue #, and add more list items as needed)

If answers are expected to change, describe (delete this line otherwise):

Any user interface changes (namelist or namelist defaults changes)?

Requirements before merge:

• I have followed the CTSM contribution guidelines.

• The code in this PR branch builds with no errors.
• The code in this PR branch runs with no errors. Briefly describe tested configuration(s):
• This either (a) does not change answers, (b) it only changes answers at roundoff level, or (c) I have performed a scientific evaluation of the answer changes. Which?:

• I have reviewed relevant parts of the CLM documentation Tech Note or User's Guide to determine if anything needs to be changed or added. If it does, describe:
• This PR either (a) does not create a need to update the documentation or (b) includes required documentation updates (see guidelines for contributing documentation). Which?:

[glemieux]

This pull request is optioned per the discussion question in NGEET/fates#1568 (comment) and is being created as a draft as a point of discussion per @wwieder suggestion. Alternatively, this PR could be superseded by adopting build namelist changes that @mvdebolskiy noted that are being integrated into NorESM/CTSM per NorESMhub#224. Since the relates to compset updates cc'ing @ekluzek for insight and input.

[ekluzek]

It's definitely a good change to simplify user-mods and put fincl/fexcl lists into the code for major configurations. fates_sp is recognized as a major configuration. So between the buioldnml and the FORTRAN code it should do what's needed to set it up, rather than having to rely on user-mods. It would be good to then be able to remove the user-mods for fates_sp.

[glemieux]

It would be good to then be able to remove the user-mods for fates_sp.

@ekluzek it sounds like you're in favor of moving this PR forward as is, correct? And that removing the fates_sp user mod would be done later? If so, I'll pull this out of draft status.

[ekluzek]

It would be good to then be able to remove the user-mods for fates_sp.

@ekluzek it sounds like you're in favor of moving this PR forward as is, correct? And that removing the fates_sp user mod would be done later? If so, I'll pull this out of draft status.

Yes absolutely!

[wwieder]

Seems like this can go to b4b-dev. @glemieux will check that it doesn't change answers in testing.