More if_re headaches for Sephe

[walt]

Hi Sephe,

I see you've already put a lot of work into the realtek driver,
and now I have another problem to report, sorry.
Your commit <d4d77345> on Oct 9, "Use hardware timer to simulate
interrupt moderation", broke the emulated realtek driver in the
kvm flavor of qemu.
The bootup ifconfig seems to go okay; 'ifconfig re0' looks like
everything *should* be working, but it seems that no packets
ever go anywhere.  Reverting the above commit fixes the problem.
Well, I should mention that during bootup, dhcp seems to work
okay -- re0 winds up with the appropriate IP address assigned
by the kvm emulated machine -- so at least *some* packets get
somewhere, but certainly not out to the internet after bootup.
But I'm not finished complaining yet :o(  The watchdog timeouts
that you recently committed a fix for are still happening for
me when running dfly under kvm. (I don't have a real machine
with a realtek nic, sorry.)
pciconf says: chip=0x813910 rev=0x20.

I'd be very happy to try any patches or diagnostic tests you
can think of.
Thanks Sephe!