tty: pass tty_port to tty functions instead of tty_struct

commit 227434f8 ("TTY: switch tty_buffer_request_room to tty_port")

started to convert all tty functions to receive a tty_port
instead of a tt_struct. Update the drivers according this
API change.

Signed-off-by: Javier Martinez Canillas <javier@dowhile0.org>
tty: update termios access due tty_struct changes

commit adc8d746 ("tty: move the termios object into the tty")

moved the struct ktermios inside struct tty_struct instead of
keeping just a pointer to it. So, let's update the access to
termios according to this change.

Signed-off-by: Javier Martinez Canillas <javier@dowhile0.org>