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/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 9295670..d4a7c24 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -774,7 +774,7 @@
 	 * uart_start(), which takes the lock.
 	 */
 	spin_unlock(&port->lock);
-	tty_flip_buffer_push(port->state->port.tty);
+	tty_flip_buffer_push(&port->state->port);
 	spin_lock(&port->lock);
 }
 
@@ -782,7 +782,6 @@
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 	struct tty_port *tport = &port->state->port;
-	struct tty_struct *tty = tport->tty;
 	struct atmel_dma_buffer *pdc;
 	int rx_idx = atmel_port->pdc_rx_idx;
 	unsigned int head;
@@ -850,7 +849,7 @@
 	 * uart_start(), which takes the lock.
 	 */
 	spin_unlock(&port->lock);
-	tty_flip_buffer_push(tty);
+	tty_flip_buffer_push(tport);
 	spin_lock(&port->lock);
 
 	UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);