drm/amdkfd: fix a potential double free in pqm_create_queue

Set *q to NULL on errors, otherwise pqm_create_queue would free it
again.

Signed-off-by: Chia-I Wu <[e-mail]>
Signed-off-by: Felix Kuehling <[e-mail]>
Reviewed-by: Felix Kuehling <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/amdkfd/kfd_process_queue_manager.c

···
 	return 0;
 
 cleanup:
-	if (dev->shared_resources.enable_mes)
-		uninit_queue(*q);
+	uninit_queue(*q);
+	*q = NULL;
 	return retval;
 }