Fix Cinema4D Import (#6062)

#5623 broke the Cinema4D import by forgetting to rename a constant. This commit fixes the invalid name.

Co-authored-by: Krishty <krishty@krishty.com>
Co-authored-by: Kim Kulling <kimkulling@users.noreply.github.com>

code/AssetLib/C4D/C4DImporter.cpp

@@ -64,7 +64,7 @@ namespace {
 
 aiString aiStringFrom(cineware::String const & cinestring) {
     aiString result;
-    cinestring.GetCString(result.data, MAXLEN-1);
+    cinestring.GetCString(result.data, AI_MAXLEN - 1);
     result.length = static_cast<ai_uint32>(cinestring.GetLength());
     return result;
 }