drm/xe/hwmon: Fix kernel version documentation for fan speed

drm/xe/hwmon: Fix kernel version documentation for fan speed

The version in the sysfs attribute should correspond to the version in
which this is enabled and visible for end users. It usually doesn't
correspond to the version in which the patch was developed, but rather a
release that will contain it. Update them to 6.16.

Fixes: 28f79ac609de ("drm/xe/hwmon: expose fan speed")
Reported-by: Ulisses Furquim <ulisses.furquim@intel.com>
Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/4841
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Raag Jadav <raag.jadav@intel.com>
Link: https://lore.kernel.org/r/20250421-hwmon-doc-fix-v1-2-9f68db702249@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>