drm/xe/hwmon: Stop ignoring errors on probe

drm/xe/hwmon: Stop ignoring errors on probe

Not registering hwmon because it's not available (SRIOV_VF and DGFX) is
different from failing the initialization. Handle the errors
appropriately.

Cc: Badal Nilawar <badal.nilawar@intel.com>
Cc: Karthik Poosa <karthik.poosa@intel.com>
Reviewed-by: Raag Jadav <raag.jadav@intel.com>
Reviewed-by: Badal Nilawar <badal.nilawar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250213192909.996148-13-lucas.demarchi@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>