Revert "Revert "debug_mm: Only print pr_debug and pr_info if DEBUG.""

This reverts commit 31188741eb8c41f27357e7c90543ca70d7fb8a35.
Revert "Revert "Fix compilation with debugfs disabled""

This reverts commit 57a8e625c7326c04c76bc78ef00088adcc6c38cf.
Revert "Revert "Fix compilation with debugfs disabled""

This reverts commit 175add61676c806f2b48a99639f181f47b0344da.
update