thermal: core: allow user configuration of hardware protection action

In the general case, we don't know which of system shutdown or reboot is
the better action to take to protect hardware in an emergency situation.
We thus allow the policy to come from the device-tree in the form of an
optional critical-action OF property, but so far there was no way for the
end user to configure this.

With recent addition of the hw_protection parameter, the user can now
choose a default action for the case, where the driver isn't fully sure
what's the better course of action.

Let's make use of this by passing HWPROT_ACT_DEFAULT in absence of the
critical-action OF property.

As HWPROT_ACT_DEFAULT is shutdown by default, this introduces no
functional change for users, unless they start using the new parameter.

Link: https://lkml.kernel.org/r/20250217-hw_protection-reboot-v3-11-e1c09b090c0c@pengutronix.de
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
Cc: Benson Leung <bleung@chromium.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Fabio Estevam <festevam@denx.de>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Lukasz Luba <lukasz.luba@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Matteo Croce <teknoraver@meta.com>
Cc: Matti Vaittinen <mazziesaccount@gmail.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Rob Herring (Arm) <robh@kernel.org>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>