Disabled the sleep in ttyflush().  It can't work in general because ttyflush() might be called from an interrupt handler.  This fixes panics in IXOFF mode at the cost of more failures to send the START character to exit from IXOFF mode.
Disabled the sleep in ttyflush().  It can't work in general because
ttyflush() might be called from an interrupt handler.  This fixes
panics in IXOFF mode at the cost of more failures to send the START
character to exit from IXOFF mode.

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase