Fixes uninitialized irq_h name

Might just remove it.
Ethernet devices register there their own IRQs

The Plan 9 way was to have one IRQ per ethernet device, which devether
registers for each NIC.  Many NICs will want separate IRQ handlers, possibly
for different queues.

Now, all NICs register and manage their own IRQs.  The old plan 9 way was to do
it in the reset/pnp method.  These resets happen during the booting process,
and for now that is the only place you can do vmap_pmem calls (which you'll
need when you register_irq for MSI-X).
x86: Kernel tries to handle user page faults

We could deadlock doing this - need to review and be careful any time we access
a user pointer.

Segvs will still cause a panic, but anon memory should work.