A number of irqchip implementations are (ab)using the irqdomain
allocator by passing a fwnode that is neither a FWNODE_OF or
a FWNODE_IRQCHIP.
This is pretty bad, but it also feels pretty crap to force these
drivers to allocate their own irqchip_fwid when they already have
a proper fwnode.
Instead, let's teach the irqdomain allocator about ACPI device
nodes, and add some lovely name generation code... Tested on
an arm64 D05 system.