[LTP] userfaultfd: Add helper for checking UFFD feature support

[Andrea Cervesato]

> The commit is there:
> 
> commit 1840ee23d172b5ab04cca7c2acfa48755b041911
> Author: Li Wang <li.wang@linux.dev>
> Date:   Fri Jan 23 19:54:19 2026 +0800
> 
>     userfaultfd05: require CONFIG_HAVE_ARCH_USERFAULTFD_WP

sigh. Im wondering why it didn't catch it, this is the basics.

I think we need to separate the logical review from everything
that can be done with a linter. I will explore this possibility
in the next weeks when I will have more time.

Regards,
--
Andrea Cervesato
SUSE QE Automation Engineer Linux
andrea.cervesato@suse.com