Merge patch series "initramfs: kunit tests and cleanups"

David Disseldorp <ddiss@suse.de> says:

This patchset adds basic kunit test coverage for initramfs unpacking
and cleans up some minor buffer handling issues / inefficiencies.

* patches from https://lore.kernel.org/r/20250304061020.9815-1-ddiss@suse.de:
  initramfs: avoid static buffer for error message
  initramfs: fix hardlink hash leak without TRAILER
  initramfs: reuse name_len for dir mtime tracking
  initramfs: allocate heap buffers together
  initramfs: avoid memcpy for hex header fields
  vsprintf: add simple_strntoul
  initramfs_test: kunit tests for initramfs unpacking
  init: add initramfs_internal.h

Link: https://lore.kernel.org/r/20250304061020.9815-1-ddiss@suse.de
Signed-off-by: Christian Brauner <brauner@kernel.org>