drm/xe: Expose fan control and voltage regulator version

drm/xe: Expose fan control and voltage regulator version

Add sysfs attributes for late binding features which expose bound version
to the user.

v2: Rework attribute and macro naming (Badal)
v3: Drop fancy formatting (Rodrigo)
v4: Form version string using local variables (Rodrigo)

Signed-off-by: Raag Jadav <raag.jadav@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://lore.kernel.org/r/20250709164224.2676086-1-raag.jadav@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>