Documentation: ioctl-number: Update table intro

Documentation: ioctl-number: Update table intro

Introduction paragraph to the ioctl numbers table states that only
ioctls in up to ancient Linux kernel version (v2.6.31) for x86 arch are
listed. This is inaccurate as the table also lists ioctls from non-x86
archs and the kernel is continously developed (currently in v6.x).

Update the paragraph accordingly.

Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20250508005838.8381-2-bagasdotme@gmail.com>