Concurrent access from main loop and the different uart irqs was not going well and caused crashes. The libosmocore fsm does still allocate one internal timer, but it is not used by the firmware, so libosmocore will not touch the rbtree.
This clashes with the host build which does not have jiffies, and is pretty much a burden because it requires special casing code due to the completely different targets even though it was last used many years ago and might not even work, so disable it.
