Clang Tidy: enable readability-non-const-parameter warning

Clang Tidy reported a couple of false positives. I disabled
those `NOLINTNEXTLINE`.

Differential Revision: https://developer.blender.org/D8199

.clang-tidy

@@ -14,7 +14,6 @@ Checks:  >
 
   -readability-else-after-return,
   -readability-inconsistent-declaration-parameter-name,
-  -readability-non-const-parameter,
   -readability-redundant-preprocessor,
   -readability-function-size,
   -readability-function-size,