Don't apply editorconfig to llvm

They use 2 spaces by default, not 4.

Author: jyn514

.editorconfig

@@ -9,6 +9,8 @@ end_of_line = lf
 charset = utf-8
 trim_trailing_whitespace = true
 insert_final_newline = true
+
+[!src/llvm-project]
 indent_style = space
 indent_size = 4