I'm not sure we want to trust the FW on that particular front (no
offence intended...;-).
That is my current take on this patch. Nothing in the arm64 kernel
expects a FIQ today, so *when* a FIQ fires is pretty much irrelevant,
as long as we handle it properly (panic). Keeping the two bits in sync
is trivial, and shouldn't carry material overhead.
Aside from the lack of programmable priority, the lack of convenient
masking for per-CPU interrupts is a bit of an issue...