drm/xe: Ensure all locks released in exec IOCTL

In couple of places the wrong error handling goto was used to release
locks. Fix these to ensure all locks dropped on exec IOCTL errors.

Cc: Francois Dugast <francois.dugast@intel.com>
Fixes: d16ef1a1 ("drm/xe/exec: Switch hw engine group execution mode upon job submission")
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Francois Dugast <francois.dugast@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241106224944.30130-1-matthew.brost@intel.com