Think the entire fe86375d1c6 is to be reverted, same as done as part of D7352 (can't link to a specific commit in the patch it seems).
Initial intention of adding BKE_multires_sculpt_level_get was to make it easy to see where access to sculpt level is to happen (if sculptlvl was replaced with lvl that'd make it more difficult to find all the cases). Now I do not see any reason to have such pass-through accessor.