staging: speakup: flush tty buffers

[Samuel Thibault]

Hello,

John Covici, on mar. 02 mai 2017 19:05:15 -0400, wrote:
> Make sure that the modem lines rts-cts are also properly switched.

Mmm, I'm afraid we forgot to set that.

It seems RTS/CTS flow control is not enabled by default.  So in ttyio
we'd need to call tty_set_termios. See how set_termios gets the current
value, on which we just need to termios.c_cflag |= CRTSCTS before
calling tty_set_termios.

Samuel