uml: fix tty-related build error

/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: Jeff Dike <jdike@addtoit.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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;
 }