TTY: switch tty_flip_buffer_push

Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty in many
call sites. Only tty_port will needed and hence no more
tty_port_tty_get in those paths.

Now, the one where most of tty_port_tty_get gets removed:
tty_flip_buffer_push.

IOW we also closed all the races in drivers not using tty_port_tty_get
at all yet.

Also we move tty_flip_buffer_push declaration from include/linux/tty.h
to include/linux/tty_flip.h to all others while we are changing it
anyway.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/ipwireless/tty.c b/drivers/tty/ipwireless/tty.c
index c43da74..8fd72ff 100644
--- a/drivers/tty/ipwireless/tty.c
+++ b/drivers/tty/ipwireless/tty.c
@@ -160,15 +160,9 @@
 void ipwireless_tty_received(struct ipw_tty *tty, unsigned char *data,
 			unsigned int length)
 {
-	struct tty_struct *linux_tty;
 	int work = 0;
 
 	mutex_lock(&tty->ipw_tty_mutex);
-	linux_tty = tty->port.tty;
-	if (linux_tty == NULL) {
-		mutex_unlock(&tty->ipw_tty_mutex);
-		return;
-	}
 
 	if (!tty->port.count) {
 		mutex_unlock(&tty->ipw_tty_mutex);
@@ -187,7 +181,7 @@
 	 * This may sleep if ->low_latency is set
 	 */
 	if (work)
-		tty_flip_buffer_push(linux_tty);
+		tty_flip_buffer_push(&tty->port);
 }
 
 static void ipw_write_packet_sent_callback(void *callback_data,