remove fms2io_init in interpolator_mod

[mlee03]

Description This PR removes the subroutine fms2io_init . All code in fms2io_init is involved in initialization and is moved to subroutine interpolator_init instead.

Fixes #1309

How Has This Been Tested? Make passes with the latest Intel and GCC on the AMD box

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [x] Any dependent changes have been merged and published in downstream modules
• [x] New check tests, if applicable, are included
• [x] make distcheck passes