Merge patch series "Revert "pid: make __task_pid_nr_ns(ns => NULL) safe for zombie...

Commit 006568ab4c5c ("pid: Add a judgment for ns null in pid_nr_ns")
already added the ns != NULL check in pid_nr_ns(), so we can remove the
same check from __task_pid_nr_ns().

* patches from https://patch.msgid.link/20251015123550.GA9447@redhat.com:
  pid: introduce task_ppid_vnr() helper
  Revert "pid: make __task_pid_nr_ns(ns => NULL) safe for zombie callers"

Link: https://patch.msgid.link/20251015123550.GA9447@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>