Remove broken "chase" implementation which was supposed to be used to
drain the write buffers at break.

The chase implementation slept on a wait queue which was never woken up
(i.e. no hardware buffers were queried), and thus amounted to nothing
more than polling chars_in_buffer, something which has already been
taken care of by the tty layer.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>