the only architecture dependence of devether was enabling interrupts,
which is now done at the end of the driver's reset() function now.
the wifi stack and dummy ethersink also go to port/.
do the IRQ2->IRQ9 hack for pc kernels in intrenabale(), so not
every caller of intrenable() has to be aware of it.
catch the error() that can be thrown by sleep() and tsleep()
in kprocs.
add missing pexit() calls.
always set the freemem argument to pexit() from kproc otherwise
the process gets added to the broken list.
