Revert "lib.modules: Remove redundant fixupOptionType in option injection"

This reverts commit 6b077c47ff.

Thanks Infinisil for discovering this problem:

> After a lot of trial and error, trying to prove why fixupOptionType should
> be used here or not, I figured it out: It's needed for the sake of file
> locations in error messages.

lib/modules.nix

@@ -527,7 +527,7 @@ rec {
               #  d. magically combine (a) and (c).
               # All of the above are merely syntax sugar though.
               then
-                let opt = mergeOptionDecls loc (map optionTreeToOption decls);
+                let opt = fixupOptionType loc (mergeOptionDecls loc (map optionTreeToOption decls));
                 in {
                   matchedOptions = evalOptionValue loc opt defns';
                   unmatchedDefns = [];