tty: Replace TTY_THROTTLED bit tests with tty_throttled()

Abstract TTY_THROTTLED bit tests with tty_throttled().

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/nozomi.c

@@ -826,7 +826,7 @@ static int receive_data(enum port_type index, struct nozomi *dc)
 	size = __le32_to_cpu(readl(addr));
 	/*  DBG1( "%d bytes port: %d", size, index); */
 
-	if (tty && test_bit(TTY_THROTTLED, &tty->flags)) {
+	if (tty && tty_throttled(tty)) {
 		DBG1("No room in tty, don't read data, don't ack interrupt, "
 			"disable interrupt");