Two fixes for the interrupt subsystem:

 - Make the handling of the firmware node consistent and do not free the
   node after the domain has been created successfully. The core code
   stores a pointer to it which can lead to a use after free or double
   free.

   This used to "work" because the pointer was not stored when the initial
   code was written, but at some point later it was required to store
   it. Of course nobody noticed that the existing users break that way.

 - Handle affinity setting on inactive interrupts correctly when
   hierarchical irq domains are enabled. When interrupts are inactive with
   the modern hierarchical irqdomain design, the interrupt chips are not
   necessarily in a state where affinity changes can be handled. The legacy
   irq chip design allowed this because interrupts are immediately fully
   initialized at allocation time. X86 has a hacky workaround for this, but
   other implementations do not. This cased malfunction on GIC-V3. Instead
   of playing whack a mole to find all affected drivers, change the core
   code to store the requested affinity setting and then establish it when
   the interrupt is allocated, which makes the X86 hack go away.