DOC: Add note that the rt kernel is recommended when ptp is configured with ice driver

[Elisamara Aoki Gonçalves]

Brief Description
-----------------

Add a note to the documentation recommending that nodes use the rt kernel when configured with ptp and the ice driver. This is because we cannot provide any guarantees for the ice driver thread priority and scheduling with the standard kernel.

PTP Introduction
https://docs.starlingx.io/system_configuration/kubernetes/ptp-introduction-d981dd710bda.html

note:
Consult the "Verified Commercial Hardware page for information on PTP compatible NICs.

Verified Commercial Hardware
https://docs.starlingx.io/planning/kubernetes/verified-commercial-hardware.html

NIC for High-precision timing synchronization with IEEE 1588 PTP, SyncE and GNSS
note:
It is recommended to configure systems to use the realtime kernel when using IEEE 1588 PTP with Intel E810 series NICs using the ice driver.
The standard kernel cannot provide any guarantees for ice driver thread priority and scheduling which can result in degraded PTP timing accuracy.

Severity
--------

<Minor: System/Feature is usable with minor issue>

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/starlingx/docs/+/900325
Committed: https://opendev.org/starlingx/docs/commit/9848b8815f9a9291de1331d84a65872f16e39a45
Submitter: "Zuul (22348)"
Branch: master

commit 9848b8815f9a9291de1331d84a65872f16e39a45
Author: Elisamara Aoki Goncalves <email address hidden>
Date: Tue Nov 7 14:32:32 2023 +0000

    Add note in Verified Commercial Hardware page (dsR8,dsR6)

    Add note that the rt kernel is recommended when ptp is configured with ice driver

    Closes-bug: 2042967

    Change-Id: I8150fcf1024bc640f1a682413406584a479d40a1
    Signed-off-by: Elisamara Aoki Goncalves <email address hidden>