GEOS-Chem submod update: Merge PR #1925 (Make OCEAN_CONC 2D)

This commit informs the GCClassic superproject about the following
commits that were pushed to the GitHub geoschem/geos-chem repository:

08838351c  Merge PR #1925 (Update OCEAN_CONC in Hg simulations from 2D to 3D)

This fixes a side-effect of HEMCO PR #235 (Bugfix in vertical
regridding) that affected the Hg simulation.

Signed-off-by: Bob Yantosca <[email protected]>