Return after warning regarding kobj creation failure.

Fixes: 4ae3aeab ("drm/xe: Add vram frequency sysfs attributes")
Cc: Sujaritha Sundaresan <sujaritha.sundaresan@intel.com>
Cc: Tejas Upadhyay <tejas.upadhyay@intel.com>
Cc: Bommu Krishnaiah <krishnaiah.bommu@intel.com>
Reviewed-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240313150545.2830408-2-himal.prasad.ghimiray@intel.comSigned-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
(cherry picked from commit 989d07ac)
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>