[Resend Patch] uml: fix a build error about tty

[WANG Cong <xiyou.wangcong@gmail.com>]

This patch fixed this error:

  CC      arch/um/drivers/line.o
  /home/wangcong/Projects/linux-2.6/arch/um/drivers/line.c: In
function ‘line_write_interrupt’:
/home/wangcong/Projects/linux-2.6/arch/um/drivers/line.c:366: error:
‘struct tty_ldisc’ has no member named ‘write_wakeup’
/home/wangcong/Projects/linux-2.6/arch/um/drivers/line.c:367: error:
‘struct tty_ldisc’ has no member named ‘write_wakeup’


Signed-off-by: WANG Cong <wangcong@zeuux.org>
Cc: jdike@addtoit.com
Acked-by: Alan Cox <alan@redhat.com>

---
diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c
index 5047490..d741f35 100644
--- a/arch/um/drivers/line.c
+++ b/arch/um/drivers/line.c
@@ -362,19 +362,7 @@ static irqreturn_t line_write_interrupt(int irq, void *data)
 	if (tty == NULL)
 		return IRQ_NONE;
 
-	if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags) &&
-	   (tty->ldisc.write_wakeup != NULL))
-		(tty->ldisc.write_wakeup)(tty);
-
-	/*
-	 * BLOCKING mode
-	 * In blocking mode, everything sleeps on tty->write_wait.
-	 * Sleeping in the console driver would break non-blocking
-	 * writes.
-	 */
-
-	if (waitqueue_active(&tty->write_wait))
-		wake_up_interruptible(&tty->write_wait);
+	tty_wakeup(tty);
 	return IRQ_HANDLED;
 }