Merge patch series "initramfs: test and improve cpio hex header validation"

David Disseldorp <ddiss@suse.de> says:

The series that introduced simple_strntoul() had passed into kernel
without proper review and hence reinvented a wheel that's not needed.
Here is the refactoring to show that. It can go via PRINTK or VFS
tree.

I have tested this on x86, but I believe the same result will be
on big-endian CPUs (I deduced that from how strtox() works).

I also run KUnit tests.

* patches from https://patch.msgid.link/20260331070519.5974-1-ddiss@suse.de:
  kstrtox: Drop extern keyword in the simple_strtox() declarations
  vsprintf: Revert "add simple_strntoul"
  initramfs: Refactor to use hex2bin() instead of custom approach
  initramfs: Sort headers alphabetically
  initramfs_test: test header fields with 0x hex prefix
  initramfs_test: add fill_cpio() inject_ox parameter

Link: https://patch.msgid.link/20260331070519.5974-1-ddiss@suse.de
Signed-off-by: Christian Brauner <brauner@kernel.org>