fs: readdir: Fix su hide patch for non-iterate filesystems

* 3.10 doesn't normally use iterate for filesystems,
  but it was backported in hopes of removing vfs_readdir()
* Because the romnt variable was only set for filesystems
  using iterate, the su hide patches were broken for many
  filesytems like ext4, which still use vfs_readdir()
  instead of iterate_dir() like their mainline counterparts
* Remove the iterate check around setting romnt to fix this

Change-Id: I26426683df0fd199a80f053294f352e31754bec5