lima/gpir: fix crash in schedule_insert_ready_list()

Fix crash if node is already at position we want. Otherwise we remove
it from list (and list->prev becomes NULL) and then we dereference list->prev
in list_addtail()

Reviewed-by: Andreas Baierl <ichgeh@imkreisrum.de>
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4126>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4126>
2 files changed