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/synclink.c b/drivers/tty/synclink.c
index 2f6967d..555fdc0 100644
--- a/drivers/tty/synclink.c
+++ b/drivers/tty/synclink.c
@@ -1439,7 +1439,6 @@
 	u16 status;
 	int work = 0;
 	unsigned char DataByte;
- 	struct tty_struct *tty = info->port.tty;
  	struct	mgsl_icount *icount = &info->icount;
 	
 	if ( debug_level >= DEBUG_LEVEL_ISR )	
@@ -1501,7 +1500,7 @@
 			if (status & RXSTATUS_BREAK_RECEIVED) {
 				flag = TTY_BREAK;
 				if (info->port.flags & ASYNC_SAK)
-					do_SAK(tty);
+					do_SAK(info->port.tty);
 			} else if (status & RXSTATUS_PARITY_ERROR)
 				flag = TTY_PARITY;
 			else if (status & RXSTATUS_FRAMING_ERROR)
@@ -1524,7 +1523,7 @@
 	}
 			
 	if(work)
-		tty_flip_buffer_push(tty);
+		tty_flip_buffer_push(&info->port);
 }
 
 /* mgsl_isr_misc()