immediately reasserted before we get a chance to process the interrupt,
we can inadvertantly get stuck with zs_tx_stopped set. Move the delta
detection to the hard zs interrupt handler; the softint handler
will notice that something has happened with CTS and restart the
transmitter if it's asserted.
independent z8530 driver. When that driver is updated, the local copy
of those files may be removed. From Bill Studenmund.
Compiler warnings fixed by me.