Merge patch series "name_is_dot* cleanup"

Amir Goldstein <amir73il@gmail.com> says:

Following the syzbot ovl bug report and a fix by Qing Wang,
I decided to follow up with a small vfs cleanup of some
open coded version of checking "." and ".." name in readdir.

The fix patch is applied at the start of this cleanup series to allow
for easy backporting, but it is not an urgent fix so I don't think
there is a need to fast track it.

* patches from https://patch.msgid.link/20260128132406.23768-1-amir73il@gmail.com:
  ovl: use name_is_dot* helpers in readdir code
  fs: add helpers name_is_dot{,dot,_dotdot}
  ovl: Fix uninit-value in ovl_fill_real

Link: https://patch.msgid.link/20260128132406.23768-1-amir73il@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>