rpi4 network boot

[Mike Karels]

Responding to one bit of this thread, so omitting most of the context:

Matthew wrote:

> I wish the boot would get that far. As shown at the bottom of my log 
> output, it hangs with the genet0 output at the end of the boot that 
> repeats endlessly in a tight loop ...

> genet0: gen_intr2
> ...

fwiw, the fdt indicates that the genet has two interrupts, but I have no
idea what the second one is for.  This is the first time I've heard of it
happening.  The interrupt routine for the second interrupt just prints
this message and returns, so we'd know that it was happening at least.

		Mike