drm/xe: Don't free job in TDR

Freeing job in TDR is not safe as TDR can pass the run_job thread
resulting in UAF. It is only safe for free job to naturally be called by
the scheduler. Rather free job in TDR, add to pending list.

Closes: drm/xe/kernel#2811


Cc: Matthew Auld <matthew.auld@intel.com>
Fixes: e275d61c ("drm/xe/guc: Handle timing out of signaled jobs gracefully")
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241003001657.3517883-3-matthew.brost@intel.com