If this is set, then don't clean the firmware at the end. This is needed to store the built firmware as artifact in jenkins, for passing it along to another job.
firmware: add tear-free 64bit load/store helpers for jiffies
On Cortex-M4 a 64bit load may compile to two separate LDR instructions which can lead to torn reads due to interrupts. LDRD/STRD are restartable, they either complete or restart from scratch, so the result is always consistent. The only "downside" is the required alignment, which is fine.
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.
Additionally ignore checkpatch jiffies complaints because we're trying to do firmware here.
This fixes the mishandling of in_progress and the queues in the submit functions that are in part irq driven, too, and ensures nothing breaks by preventing concurrent access from irqs to the queues. Applying the same pattern to all functions/cases is fine either way.
On top of all of tha the out ep was irq driven, so if submit_next_out fails it was stuck, now fixed by attempted submit from main loop, and of course the queue manipulation should be irq safe here as well.
