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/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index ec90651..6f3dbf7 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -483,7 +483,6 @@
 static irqreturn_t serial_omap_irq(int irq, void *dev_id)
 {
 	struct uart_omap_port *up = dev_id;
-	struct tty_struct *tty = up->port.state->port.tty;
 	unsigned int iir, lsr;
 	unsigned int type;
 	irqreturn_t ret = IRQ_NONE;
@@ -530,7 +529,7 @@
 
 	spin_unlock(&up->port.lock);
 
-	tty_flip_buffer_push(tty);
+	tty_flip_buffer_push(&up->port.state->port);
 
 	pm_runtime_mark_last_busy(up->dev);
 	pm_runtime_put_autosuspend(up->dev);