TTY: switch tty_insert_flip_char

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.

tty_insert_flip_char is the next one to proceed. This one is used all
over the code, so the patch is huge.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 2ea70a6..b00110c 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -332,7 +332,7 @@
 	else {
 		for (i = 0; i < urb->actual_length; i++, ch++) {
 			if (!usb_serial_handle_sysrq_char(port, *ch))
-				tty_insert_flip_char(tty, *ch, TTY_NORMAL);
+				tty_insert_flip_char(&port->port, *ch, TTY_NORMAL);
 		}
 	}
 	tty_flip_buffer_push(tty);