No impact: return statement cleanup

[scrasmussen]

TYPE: no impact

KEYWORDS: code clean up

SOURCE: Soren Rasmussen, NCAR

DESCRIPTION OF CHANGES: Code cleanup: removal of redundant 'return' statements before an 'end subroutine' statement

TESTS CONDUCTED: Built and ran with Croton to double check. Shouldn't change functionality at all

Checklist

• [ ] Closes issue #xxxx (An issue must exist or be created to be closed. The issue describes and documents the problem and general solution, the PR describes the technical details of the solution.)
• [ ] Tests added (unit tests and/or regression/integration tests)
• [X] Backwards compatible
• [ ] Requires new files? If so, how to generate them.
• [ ] Documentation included
• [ ] Short description in the Development section of NEWS.md