dead hvc_console with kdump kernel

[Benjamin Herrenschmidt]

> On real xics it is safe to do in the initial register irq.  Don't
> do it every irq register though.
> 
> Hypervisor will cover us for emulated xics if we do that.
> 
> For real mpic?  I don't know.  Maybe we do an mpic reset and that
> will cover us?  Ben?

We should probably eoi all pending interrupts. That's especially true
with machines with HT APICs like the js2x or the quad g5 since if we
don't EOI on the APIC, the interrupt will remain blocked.

Ben