drm/xe/pmu: Fail probe if xe_pmu_register() fails

drm/xe/pmu: Fail probe if xe_pmu_register() fails

Now that previous callers in xe_device_probe() are handling the errors,
that can be done for xe_pmu_register() as well.

Cc: Riana Tauro <riana.tauro@intel.com>
Cc: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Reviewed-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250213192909.996148-12-lucas.demarchi@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>