Fix MPT + GNU bug at NAS

[mathomp4]

Description

This fixes #2344 by renaming a variable from mpi_comm to comm. My theory is MPT weird because I have to build modules for GNU at NAS. This is not a bug in MAPL, more in MPT, but it's easier to just work around it in MAPL.

Related Issue

Closes #2344

Motivation and Context

Let's the model build at NAS with GNU.

How Has This Been Tested?

If this builds, it should be good.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Trivial change (affects only documentation or cleanup)

Checklist:

• I have tested this change with a run of GEOSgcm (if non-trivial)
• I have added one of the required labels (0 diff, 0 diff trivial, 0 diff structural, non 0-diff)
• I have updated the CHANGELOG.md accordingly following the style of Keep a Changelog