updated patch with throttling

[Duncan Sands]

Hi Roman,

> Right, and for reception it's even worse: if you happen to fail to
> submit all urbs you have (and we usually have very few, default 2
> originally and 4 in my patch), then they'll never complete and noone
> will reschedule the tasklet.

correct, and this was quite deliberate: since I never saw an urb failure
with the modem (except when it is unplugged), it seemed pointless to do
anything more sophisticated.  Especially as I was never too clear about
what exactly needed to be done - does the modem need to be reset in some
way for example?

Ciao,

D.